New in version 3.4.
Source code: Lib/tracemalloc.py
The tracemalloc module is a debug tool to trace memory blocks allocated by Python. It provides the following information:
To trace most memory blocks allocated by Python, the module should be started as early as possible by setting the PYTHONTRACEMALLOC environment variable to 1, or by using -X tracemalloc command line option. The tracemalloc.start() function can be called at runtime to start tracing Python memory allocations.
By default, a trace of an allocated memory block only stores the most recent frame (1 frame). To store 25 frames at startup: set the PYTHONTRACEMALLOC environment variable to 25, or use the -X tracemalloc=25 command line option.
Display the 10 files allocating the most memory:
Example of output of the Python test suite:
We can see that Python loaded 4855 KiB data (bytecode and constants) from modules and that the collections module allocated 244 KiB to build namedtuple types.
See Snapshot.statistics() for more options.
Take two snapshots and display the differences:
Example of output before/after running some tests of the Python test suite:
We can see that Python has loaded 8173 KiB of module data (bytecode and constants), and that this is 4428 KiB more than had been loaded before the tests, when the previous snapshot was taken. Similarly, the linecache module has cached 940 KiB of Python source code to format tracebacks, all of it since the previous snapshot.
If the system has little free memory, snapshots can be written on disk using the Snapshot.dump() method to analyze the snapshot offline. Then use the Snapshot.load() method reload the snapshot.
Code to display the traceback of the biggest memory block:
Example of output of the Python test suite (traceback limited to 25 frames):
We can see that the most memory was allocated in the importlib module to load data (bytecode and constants) from modules: 870.1 KiB. The traceback is where the importlib loaded data most recently: on the import pdb line of the doctest module. The traceback may change if a new module is loaded.
Code to display the 10 lines allocating the most memory with a pretty output, ignoring <frozen importlib._bootstrap> and <unknown> files:
Example of output of the Python test suite:
See Snapshot.statistics() for more options.
The following code computes two sums like 0 + 1 + 2 + ... inefficiently, by creating a list of those numbers. This list consumes a lot of memory temporarily. We can use get_traced_memory() and reset_peak() to observe the small memory usage after the sum is computed as well as the peak memory usage during the computations:
Output:
Using reset_peak() ensured we could accurately record the peak during the computation of small_sum, even though it is much smaller than the overall peak size of memory blocks since the start() call. Without the call to reset_peak(), second_peak would still be the peak from the computation large_sum (that is, equal to first_peak). In this case, both peaks are much higher than the final memory usage, and which suggests we could optimise (by removing the unnecessary call to list, and writing sum(range(...))).
Clear traces of memory blocks allocated by Python.
See also stop().
Get the traceback where the Python object obj was allocated. Return a Traceback instance, or None if the tracemalloc module is not tracing memory allocations or did not trace the allocation of the object.
See also gc.get_referrers() and sys.getsizeof() functions.
Get the maximum number of frames stored in the traceback of a trace.
The tracemalloc module must be tracing memory allocations to get the limit, otherwise an exception is raised.
The limit is set by the start() function.
Get the current size and peak size of memory blocks traced by the tracemalloc module as a tuple: (current: int, peak: int).
Set the peak size of memory blocks traced by the tracemalloc module to the current size.
Do nothing if the tracemalloc module is not tracing memory allocations.
This function only modifies the recorded peak size, and does not modify or clear any traces, unlike clear_traces(). Snapshots taken with take_snapshot() before a call to reset_peak() can be meaningfully compared to snapshots taken after the call.
See also get_traced_memory().
New in version 3.9.
Get the memory usage in bytes of the tracemalloc module used to store traces of memory blocks. Return an int.
True if the tracemalloc module is tracing Python memory allocations, False otherwise.
See also start() and stop() functions.
Start tracing Python memory allocations: install hooks on Python memory allocators. Collected tracebacks of traces will be limited to nframe frames. By default, a trace of a memory block only stores the most recent frame: the limit is 1. nframe must be greater or equal to 1.
You can still read the original number of total frames that composed the traceback by looking at the Traceback.total_nframe attribute.
Storing more than 1 frame is only useful to compute statistics grouped by 'traceback' or to compute cumulative statistics: see the Snapshot.compare_to() and Snapshot.statistics() methods.
Storing more frames increases the memory and CPU overhead of the tracemalloc module. Use the get_tracemalloc_memory() function to measure how much memory is used by the tracemalloc module.
The PYTHONTRACEMALLOC environment variable (PYTHONTRACEMALLOC=NFRAME) and the -X tracemalloc=NFRAME command line option can be used to start tracing at startup.
See also stop(), is_tracing() and get_traceback_limit() functions.
Stop tracing Python memory allocations: uninstall hooks on Python memory allocators. Also clears all previously collected traces of memory blocks allocated by Python.
Call take_snapshot() function to take a snapshot of traces before clearing them.
See also start(), is_tracing() and clear_traces() functions.
Take a snapshot of traces of memory blocks allocated by Python. Return a new Snapshot instance.
The snapshot does not include memory blocks allocated before the tracemalloc module started to trace memory allocations.
Tracebacks of traces are limited to get_traceback_limit() frames. Use the nframe parameter of the start() function to store more frames.
The tracemalloc module must be tracing memory allocations to take a snapshot, see the start() function.
See also the get_object_traceback() function.
Filter traces of memory blocks by their address space (domain).
New in version 3.6.
If inclusive is True (include), match memory blocks allocated in the address space domain.
If inclusive is False (exclude), match memory blocks not allocated in the address space domain.
Address space of a memory block (int). Read-only property.
Filter on traces of memory blocks.
See the fnmatch.fnmatch() function for the syntax of filename_pattern. The '.pyc' file extension is replaced with '.py'.
Examples:
Changed in version 3.5: The '.pyo' file extension is no longer replaced with '.py'.
Changed in version 3.6: Added the domain attribute.
Address space of a memory block (int or None).
tracemalloc uses the domain 0 to trace memory allocations made by Python. C extensions can use other domains to trace other resources.
If inclusive is True (include), only match memory blocks allocated in a file with a name matching filename_pattern at line number lineno.
If inclusive is False (exclude), ignore memory blocks allocated in a file with a name matching filename_pattern at line number lineno.
Line number (int) of the filter. If lineno is None, the filter matches any line number.
Filename pattern of the filter (str). Read-only property.
If all_frames is True, all frames of the traceback are checked. If all_frames is False, only the most recent frame is checked.
This attribute has no effect if the traceback limit is 1. See the get_traceback_limit() function and Snapshot.traceback_limit attribute.
Frame of a traceback.
The Traceback class is a sequence of Frame instances.
Filename (str).
Line number (int).
Snapshot of traces of memory blocks allocated by Python.
The take_snapshot() function creates a snapshot instance.
Compute the differences with an old snapshot. Get statistics as a sorted list of StatisticDiff instances grouped by key_type.
See the Snapshot.statistics() method for key_type and cumulative parameters.
The result is sorted from the biggest to the smallest by: absolute value of StatisticDiff.size_diff, StatisticDiff.size, absolute value of StatisticDiff.count_diff, Statistic.count and then by StatisticDiff.traceback.
Write the snapshot into a file.
Use load() to reload the snapshot.
Create a new Snapshot instance with a filtered traces sequence, filters is a list of DomainFilter and Filter instances. If filters is an empty list, return a new Snapshot instance with a copy of the traces.
All inclusive filters are applied at once, a trace is ignored if no inclusive filters match it. A trace is ignored if at least one exclusive filter matches it.
Changed in version 3.6: DomainFilter instances are now also accepted in filters.
Load a snapshot from a file.
See also dump().
Get statistics as a sorted list of Statistic instances grouped by key_type:
key_type
description
'filename'
filename
'lineno'
filename and line number
'traceback'
traceback
If cumulative is True, cumulate size and count of memory blocks of all frames of the traceback of a trace, not only the most recent frame. The cumulative mode can only be used with key_type equals to 'filename' and 'lineno'.
The result is sorted from the biggest to the smallest by: Statistic.size, Statistic.count and then by Statistic.traceback.
Maximum number of frames stored in the traceback of traces: result of the get_traceback_limit() when the snapshot was taken.
Traces of all memory blocks allocated by Python: sequence of Trace instances.
The sequence has an undefined order. Use the Snapshot.statistics() method to get a sorted list of statistics.
Statistic on memory allocations.
Snapshot.statistics() returns a list of Statistic instances.
See also the StatisticDiff class.
Number of memory blocks (int).
Total size of memory blocks in bytes (int).
Traceback where the memory block was allocated, Traceback instance.
Statistic difference on memory allocations between an old and a new Snapshot instance.
Snapshot.compare_to() returns a list of StatisticDiff instances. See also the Statistic class.
Number of memory blocks in the new snapshot (int): 0 if the memory blocks have been released in the new snapshot.
Difference of number of memory blocks between the old and the new snapshots (int): 0 if the memory blocks have been allocated in the new snapshot.
Total size of memory blocks in bytes in the new snapshot (int): 0 if the memory blocks have been released in the new snapshot.
Difference of total size of memory blocks in bytes between the old and the new snapshots (int): 0 if the memory blocks have been allocated in the new snapshot.
Traceback where the memory blocks were allocated, Traceback instance.
Trace of a memory block.
The Snapshot.traces attribute is a sequence of Trace instances.
Changed in version 3.6: Added the domain attribute.
Address space of a memory block (int). Read-only property.
tracemalloc uses the domain 0 to trace memory allocations made by Python. C extensions can use other domains to trace other resources.
Size of the memory block in bytes (int).
Traceback where the memory block was allocated, Traceback instance.
Sequence of Frame instances sorted from the oldest frame to the most recent frame.
A traceback contains at least 1 frame. If the tracemalloc module failed to get a frame, the filename "<unknown>" at line number 0 is used.
When a snapshot is taken, tracebacks of traces are limited to get_traceback_limit() frames. See the take_snapshot() function. The original number of frames of the traceback is stored in the Traceback.total_nframe attribute. That allows to know if a traceback has been truncated by the traceback limit.
The Trace.traceback attribute is an instance of Traceback instance.
Changed in version 3.7: Frames are now sorted from the oldest to the most recent, instead of most recent to oldest.
Total number of frames that composed the traceback before truncation. This attribute can be set to None if the information is not available.
Changed in version 3.9: The Traceback.total_nframe attribute was added.
Format the traceback as a list of lines with newlines. Use the linecache module to retrieve lines from the source code. If limit is set, format the limit most recent frames if limit is positive. Otherwise, format the abs(limit) oldest frames. If most_recent_first is True, the order of the formatted frames is reversed, returning the most recent frame first instead of last.
Similar to the traceback.format_tb() function, except that format() does not include newlines.
Example:
Output:


Clear traces of memory blocks allocated by Python.
See also stop().


Filter traces of memory blocks by their address space (domain).
New in version 3.6.
If inclusive is True (include), match memory blocks allocated in the address space domain.
If inclusive is False (exclude), match memory blocks not allocated in the address space domain.
Address space of a memory block (int). Read-only property.


Address space of a memory block (int). Read-only property.


If inclusive is True (include), match memory blocks allocated in the address space domain.
If inclusive is False (exclude), match memory blocks not allocated in the address space domain.


Filter on traces of memory blocks.
See the fnmatch.fnmatch() function for the syntax of filename_pattern. The '.pyc' file extension is replaced with '.py'.
Examples:
Changed in version 3.5: The '.pyo' file extension is no longer replaced with '.py'.
Changed in version 3.6: Added the domain attribute.
Address space of a memory block (int or None).
tracemalloc uses the domain 0 to trace memory allocations made by Python. C extensions can use other domains to trace other resources.
If inclusive is True (include), only match memory blocks allocated in a file with a name matching filename_pattern at line number lineno.
If inclusive is False (exclude), ignore memory blocks allocated in a file with a name matching filename_pattern at line number lineno.
Line number (int) of the filter. If lineno is None, the filter matches any line number.
Filename pattern of the filter (str). Read-only property.
If all_frames is True, all frames of the traceback are checked. If all_frames is False, only the most recent frame is checked.
This attribute has no effect if the traceback limit is 1. See the get_traceback_limit() function and Snapshot.traceback_limit attribute.


If all_frames is True, all frames of the traceback are checked. If all_frames is False, only the most recent frame is checked.
This attribute has no effect if the traceback limit is 1. See the get_traceback_limit() function and Snapshot.traceback_limit attribute.


Address space of a memory block (int or None).
tracemalloc uses the domain 0 to trace memory allocations made by Python. C extensions can use other domains to trace other resources.


Filename pattern of the filter (str). Read-only property.


If inclusive is True (include), only match memory blocks allocated in a file with a name matching filename_pattern at line number lineno.
If inclusive is False (exclude), ignore memory blocks allocated in a file with a name matching filename_pattern at line number lineno.


Line number (int) of the filter. If lineno is None, the filter matches any line number.


Frame of a traceback.
The Traceback class is a sequence of Frame instances.
Filename (str).
Line number (int).


Get the traceback where the Python object obj was allocated. Return a Traceback instance, or None if the tracemalloc module is not tracing memory allocations or did not trace the allocation of the object.
See also gc.get_referrers() and sys.getsizeof() functions.


Get the maximum number of frames stored in the traceback of a trace.
The tracemalloc module must be tracing memory allocations to get the limit, otherwise an exception is raised.
The limit is set by the start() function.


Get the current size and peak size of memory blocks traced by the tracemalloc module as a tuple: (current: int, peak: int).


Get the memory usage in bytes of the tracemalloc module used to store traces of memory blocks. Return an int.


True if the tracemalloc module is tracing Python memory allocations, False otherwise.
See also start() and stop() functions.


Set the peak size of memory blocks traced by the tracemalloc module to the current size.
Do nothing if the tracemalloc module is not tracing memory allocations.
This function only modifies the recorded peak size, and does not modify or clear any traces, unlike clear_traces(). Snapshots taken with take_snapshot() before a call to reset_peak() can be meaningfully compared to snapshots taken after the call.
See also get_traced_memory().
New in version 3.9.


Snapshot of traces of memory blocks allocated by Python.
The take_snapshot() function creates a snapshot instance.
Compute the differences with an old snapshot. Get statistics as a sorted list of StatisticDiff instances grouped by key_type.
See the Snapshot.statistics() method for key_type and cumulative parameters.
The result is sorted from the biggest to the smallest by: absolute value of StatisticDiff.size_diff, StatisticDiff.size, absolute value of StatisticDiff.count_diff, Statistic.count and then by StatisticDiff.traceback.
Write the snapshot into a file.
Use load() to reload the snapshot.
Create a new Snapshot instance with a filtered traces sequence, filters is a list of DomainFilter and Filter instances. If filters is an empty list, return a new Snapshot instance with a copy of the traces.
All inclusive filters are applied at once, a trace is ignored if no inclusive filters match it. A trace is ignored if at least one exclusive filter matches it.
Changed in version 3.6: DomainFilter instances are now also accepted in filters.
Load a snapshot from a file.
See also dump().
Get statistics as a sorted list of Statistic instances grouped by key_type:
key_type
description
'filename'
filename
'lineno'
filename and line number
'traceback'
traceback
If cumulative is True, cumulate size and count of memory blocks of all frames of the traceback of a trace, not only the most recent frame. The cumulative mode can only be used with key_type equals to 'filename' and 'lineno'.
The result is sorted from the biggest to the smallest by: Statistic.size, Statistic.count and then by Statistic.traceback.
Maximum number of frames stored in the traceback of traces: result of the get_traceback_limit() when the snapshot was taken.
Traces of all memory blocks allocated by Python: sequence of Trace instances.
The sequence has an undefined order. Use the Snapshot.statistics() method to get a sorted list of statistics.


Compute the differences with an old snapshot. Get statistics as a sorted list of StatisticDiff instances grouped by key_type.
See the Snapshot.statistics() method for key_type and cumulative parameters.
The result is sorted from the biggest to the smallest by: absolute value of StatisticDiff.size_diff, StatisticDiff.size, absolute value of StatisticDiff.count_diff, Statistic.count and then by StatisticDiff.traceback.


Write the snapshot into a file.
Use load() to reload the snapshot.


Create a new Snapshot instance with a filtered traces sequence, filters is a list of DomainFilter and Filter instances. If filters is an empty list, return a new Snapshot instance with a copy of the traces.
All inclusive filters are applied at once, a trace is ignored if no inclusive filters match it. A trace is ignored if at least one exclusive filter matches it.
Changed in version 3.6: DomainFilter instances are now also accepted in filters.


Load a snapshot from a file.
See also dump().


Get statistics as a sorted list of Statistic instances grouped by key_type:
key_type
description
'filename'
filename
'lineno'
filename and line number
'traceback'
traceback
If cumulative is True, cumulate size and count of memory blocks of all frames of the traceback of a trace, not only the most recent frame. The cumulative mode can only be used with key_type equals to 'filename' and 'lineno'.
The result is sorted from the biggest to the smallest by: Statistic.size, Statistic.count and then by Statistic.traceback.


Maximum number of frames stored in the traceback of traces: result of the get_traceback_limit() when the snapshot was taken.


Traces of all memory blocks allocated by Python: sequence of Trace instances.
The sequence has an undefined order. Use the Snapshot.statistics() method to get a sorted list of statistics.


Start tracing Python memory allocations: install hooks on Python memory allocators. Collected tracebacks of traces will be limited to nframe frames. By default, a trace of a memory block only stores the most recent frame: the limit is 1. nframe must be greater or equal to 1.
You can still read the original number of total frames that composed the traceback by looking at the Traceback.total_nframe attribute.
Storing more than 1 frame is only useful to compute statistics grouped by 'traceback' or to compute cumulative statistics: see the Snapshot.compare_to() and Snapshot.statistics() methods.
Storing more frames increases the memory and CPU overhead of the tracemalloc module. Use the get_tracemalloc_memory() function to measure how much memory is used by the tracemalloc module.
The PYTHONTRACEMALLOC environment variable (PYTHONTRACEMALLOC=NFRAME) and the -X tracemalloc=NFRAME command line option can be used to start tracing at startup.
See also stop(), is_tracing() and get_traceback_limit() functions.


Statistic on memory allocations.
Snapshot.statistics() returns a list of Statistic instances.
See also the StatisticDiff class.
Number of memory blocks (int).
Total size of memory blocks in bytes (int).
Traceback where the memory block was allocated, Traceback instance.


Total size of memory blocks in bytes (int).


Traceback where the memory block was allocated, Traceback instance.


Statistic difference on memory allocations between an old and a new Snapshot instance.
Snapshot.compare_to() returns a list of StatisticDiff instances. See also the Statistic class.
Number of memory blocks in the new snapshot (int): 0 if the memory blocks have been released in the new snapshot.
Difference of number of memory blocks between the old and the new snapshots (int): 0 if the memory blocks have been allocated in the new snapshot.
Total size of memory blocks in bytes in the new snapshot (int): 0 if the memory blocks have been released in the new snapshot.
Difference of total size of memory blocks in bytes between the old and the new snapshots (int): 0 if the memory blocks have been allocated in the new snapshot.
Traceback where the memory blocks were allocated, Traceback instance.


Number of memory blocks in the new snapshot (int): 0 if the memory blocks have been released in the new snapshot.


Difference of number of memory blocks between the old and the new snapshots (int): 0 if the memory blocks have been allocated in the new snapshot.


Total size of memory blocks in bytes in the new snapshot (int): 0 if the memory blocks have been released in the new snapshot.


Difference of total size of memory blocks in bytes between the old and the new snapshots (int): 0 if the memory blocks have been allocated in the new snapshot.


Traceback where the memory blocks were allocated, Traceback instance.


Stop tracing Python memory allocations: uninstall hooks on Python memory allocators. Also clears all previously collected traces of memory blocks allocated by Python.
Call take_snapshot() function to take a snapshot of traces before clearing them.
See also start(), is_tracing() and clear_traces() functions.


Take a snapshot of traces of memory blocks allocated by Python. Return a new Snapshot instance.
The snapshot does not include memory blocks allocated before the tracemalloc module started to trace memory allocations.
Tracebacks of traces are limited to get_traceback_limit() frames. Use the nframe parameter of the start() function to store more frames.
The tracemalloc module must be tracing memory allocations to take a snapshot, see the start() function.
See also the get_object_traceback() function.


Trace of a memory block.
The Snapshot.traces attribute is a sequence of Trace instances.
Changed in version 3.6: Added the domain attribute.
Address space of a memory block (int). Read-only property.
tracemalloc uses the domain 0 to trace memory allocations made by Python. C extensions can use other domains to trace other resources.
Size of the memory block in bytes (int).
Traceback where the memory block was allocated, Traceback instance.


Address space of a memory block (int). Read-only property.
tracemalloc uses the domain 0 to trace memory allocations made by Python. C extensions can use other domains to trace other resources.


Size of the memory block in bytes (int).


Sequence of Frame instances sorted from the oldest frame to the most recent frame.
A traceback contains at least 1 frame. If the tracemalloc module failed to get a frame, the filename "<unknown>" at line number 0 is used.
When a snapshot is taken, tracebacks of traces are limited to get_traceback_limit() frames. See the take_snapshot() function. The original number of frames of the traceback is stored in the Traceback.total_nframe attribute. That allows to know if a traceback has been truncated by the traceback limit.
The Trace.traceback attribute is an instance of Traceback instance.
Changed in version 3.7: Frames are now sorted from the oldest to the most recent, instead of most recent to oldest.
Total number of frames that composed the traceback before truncation. This attribute can be set to None if the information is not available.
Changed in version 3.9: The Traceback.total_nframe attribute was added.
Format the traceback as a list of lines with newlines. Use the linecache module to retrieve lines from the source code. If limit is set, format the limit most recent frames if limit is positive. Otherwise, format the abs(limit) oldest frames. If most_recent_first is True, the order of the formatted frames is reversed, returning the most recent frame first instead of last.
Similar to the traceback.format_tb() function, except that format() does not include newlines.
Example:
Output:


Format the traceback as a list of lines with newlines. Use the linecache module to retrieve lines from the source code. If limit is set, format the limit most recent frames if limit is positive. Otherwise, format the abs(limit) oldest frames. If most_recent_first is True, the order of the formatted frames is reversed, returning the most recent frame first instead of last.
Similar to the traceback.format_tb() function, except that format() does not include newlines.
Example:
Output:


Total number of frames that composed the traceback before truncation. This attribute can be set to None if the information is not available.


The true value of the bool type. Assignments to True are illegal and raise a SyntaxError.


Source code: Lib/tty.py
The tty module defines functions for putting the tty into cbreak and raw modes.
Because it requires the termios module, it will work only on Unix.
The tty module defines the following functions:
Change the mode of the file descriptor fd to raw. If when is omitted, it defaults to termios.TCSAFLUSH, and is passed to termios.tcsetattr().
Change the mode of file descriptor fd to cbreak. If when is omitted, it defaults to termios.TCSAFLUSH, and is passed to termios.tcsetattr().
See also
Low-level terminal control interface.


Change the mode of file descriptor fd to cbreak. If when is omitted, it defaults to termios.TCSAFLUSH, and is passed to termios.tcsetattr().


Change the mode of the file descriptor fd to raw. If when is omitted, it defaults to termios.TCSAFLUSH, and is passed to termios.tcsetattr().


Tuples may be constructed in a number of ways:
The constructor builds a tuple whose items are the same and in the same order as iterable’s items. iterable may be either a sequence, a container that supports iteration, or an iterator object. If iterable is already a tuple, it is returned unchanged. For example, tuple('abc') returns ('a', 'b', 'c') and tuple( [1, 2, 3] ) returns (1, 2, 3). If no argument is given, the constructor creates a new empty tuple, ().
Note that it is actually the comma which makes a tuple, not the parentheses. The parentheses are optional, except in the empty tuple case, or when they are needed to avoid syntactic ambiguity. For example, f(a, b, c) is a function call with three arguments, while f((a, b, c)) is a function call with a 3-tuple as the sole argument.
Tuples implement all of the common sequence operations.


Rather than being a function, tuple is actually an immutable sequence type, as documented in Tuples and Sequence Types — list, tuple, range.


Source code: Lib/turtle.py
Turtle graphics is a popular way for introducing programming to kids. It was part of the original Logo programming language developed by Wally Feurzeig, Seymour Papert and Cynthia Solomon in 1967.
Imagine a robotic turtle starting at (0, 0) in the x-y plane. After an import turtle, give it the command turtle.forward(15), and it moves (on-screen!) 15 pixels in the direction it is facing, drawing a line as it moves. Give it the command turtle.right(25), and it rotates in-place 25 degrees clockwise.
Turtle star
Turtle can draw intricate shapes using programs that repeat simple moves.
By combining together these and similar commands, intricate shapes and pictures can easily be drawn.
The turtle module is an extended reimplementation of the same-named module from the Python standard distribution up to version Python 2.5.
It tries to keep the merits of the old turtle module and to be (nearly) 100% compatible with it. This means in the first place to enable the learning programmer to use all the commands, classes and methods interactively when using the module from within IDLE run with the -n switch.
The turtle module provides turtle graphics primitives, in both object-oriented and procedure-oriented ways. Because it uses tkinter for the underlying graphics, it needs a version of Python installed with Tk support.
The object-oriented interface uses essentially two+two classes:
The TurtleScreen class defines graphics windows as a playground for the drawing turtles. Its constructor needs a tkinter.Canvas or a ScrolledCanvas as argument. It should be used when turtle is used as part of some application.
The function Screen() returns a singleton object of a TurtleScreen subclass. This function should be used when turtle is used as a standalone tool for doing graphics. As a singleton object, inheriting from its class is not possible.
All methods of TurtleScreen/Screen also exist as functions, i.e. as part of the procedure-oriented interface.
RawTurtle (alias: RawPen) defines Turtle objects which draw on a TurtleScreen. Its constructor needs a Canvas, ScrolledCanvas or TurtleScreen as argument, so the RawTurtle objects know where to draw.
Derived from RawTurtle is the subclass Turtle (alias: Pen), which draws on “the” Screen instance which is automatically created, if not already present.
All methods of RawTurtle/Turtle also exist as functions, i.e. part of the procedure-oriented interface.
The procedural interface provides functions which are derived from the methods of the classes Screen and Turtle. They have the same names as the corresponding methods. A screen object is automatically created whenever a function derived from a Screen method is called. An (unnamed) turtle object is automatically created whenever any of the functions derived from a Turtle method is called.
To use multiple turtles on a screen one has to use the object-oriented interface.
Note
In the following documentation the argument list for functions is given. Methods, of course, have the additional first argument self which is omitted here.
Most of the examples in this section refer to a Turtle instance called turtle.
distance – a number (integer or float)
Move the turtle forward by the specified distance, in the direction the turtle is headed.
distance – a number
Move the turtle backward by distance, opposite to the direction the turtle is headed. Do not change the turtle’s heading.
angle – a number (integer or float)
Turn turtle right by angle units. (Units are by default degrees, but can be set via the degrees() and radians() functions.) Angle orientation depends on the turtle mode, see mode().
angle – a number (integer or float)
Turn turtle left by angle units. (Units are by default degrees, but can be set via the degrees() and radians() functions.) Angle orientation depends on the turtle mode, see mode().
If y is None, x must be a pair of coordinates or a Vec2D (e.g. as returned by pos()).
Move turtle to an absolute position. If the pen is down, draw line. Do not change the turtle’s orientation.
x – a number (integer or float)
Set the turtle’s first coordinate to x, leave second coordinate unchanged.
y – a number (integer or float)
Set the turtle’s second coordinate to y, leave first coordinate unchanged.
to_angle – a number (integer or float)
Set the orientation of the turtle to to_angle. Here are some common directions in degrees:
standard mode
logo mode
0 - east
0 - north
90 - north
90 - east
180 - west
180 - south
270 - south
270 - west
Move turtle to the origin – coordinates (0,0) – and set its heading to its start-orientation (which depends on the mode, see mode()).
Draw a circle with given radius. The center is radius units left of the turtle; extent – an angle – determines which part of the circle is drawn. If extent is not given, draw the entire circle. If extent is not a full circle, one endpoint of the arc is the current pen position. Draw the arc in counterclockwise direction if radius is positive, otherwise in clockwise direction. Finally the direction of the turtle is changed by the amount of extent.
As the circle is approximated by an inscribed regular polygon, steps determines the number of steps to use. If not given, it will be calculated automatically. May be used to draw regular polygons.
Draw a circular dot with diameter size, using color. If size is not given, the maximum of pensize+4 and 2*pensize is used.
Stamp a copy of the turtle shape onto the canvas at the current turtle position. Return a stamp_id for that stamp, which can be used to delete it by calling clearstamp(stamp_id).
stampid – an integer, must be return value of previous stamp() call
Delete stamp with given stampid.
n – an integer (or None)
Delete all or first/last n of turtle’s stamps. If n is None, delete all stamps, if n > 0 delete first n stamps, else if n < 0 delete last n stamps.
Undo (repeatedly) the last turtle action(s). Number of available undo actions is determined by the size of the undobuffer.
speed – an integer in the range 0..10 or a speedstring (see below)
Set the turtle’s speed to an integer value in the range 0..10. If no argument is given, return current speed.
If input is a number greater than 10 or smaller than 0.5, speed is set to 0. Speedstrings are mapped to speedvalues as follows:
Speeds from 1 to 10 enforce increasingly faster animation of line drawing and turtle turning.
Attention: speed = 0 means that no animation takes place. forward/back makes turtle jump and likewise left/right make the turtle turn instantly.
Return the turtle’s current location (x,y) (as a Vec2D vector).
Return the angle between the line from turtle position to position specified by (x,y), the vector or the other turtle. This depends on the turtle’s start orientation which depends on the mode - “standard”/”world” or “logo”.
Return the turtle’s x coordinate.
Return the turtle’s y coordinate.
Return the turtle’s current heading (value depends on the turtle mode, see mode()).
Return the distance from the turtle to (x,y), the given vector, or the given other turtle, in turtle step units.
fullcircle – a number
Set angle measurement units, i.e. set number of “degrees” for a full circle. Default value is 360 degrees.
Set the angle measurement units to radians. Equivalent to degrees(2*math.pi).
Pull the pen down – drawing when moving.
Pull the pen up – no drawing when moving.
width – a positive number
Set the line thickness to width or return it. If resizemode is set to “auto” and turtleshape is a polygon, that polygon is drawn with the same line thickness. If no argument is given, the current pensize is returned.
Return or set the pen’s attributes in a “pen-dictionary” with the following key/value pairs:
This dictionary can be used as argument for a subsequent call to pen() to restore the former pen-state. Moreover one or more of these attributes can be provided as keyword-arguments. This can be used to set several pen attributes in one statement.
Return True if pen is down, False if it’s up.
Return or set the pencolor.
Four input formats are allowed:
Return the current pencolor as color specification string or as a tuple (see example). May be used as input to another color/pencolor/fillcolor call.
Set pencolor to colorstring, which is a Tk color specification string, such as "red", "yellow", or "#33cc8c".
Set pencolor to the RGB color represented by the tuple of r, g, and b. Each of r, g, and b must be in the range 0..colormode, where colormode is either 1.0 or 255 (see colormode()).
Set pencolor to the RGB color represented by r, g, and b. Each of r, g, and b must be in the range 0..colormode.
If turtleshape is a polygon, the outline of that polygon is drawn with the newly set pencolor.
Return or set the fillcolor.
Four input formats are allowed:
Return the current fillcolor as color specification string, possibly in tuple format (see example). May be used as input to another color/pencolor/fillcolor call.
Set fillcolor to colorstring, which is a Tk color specification string, such as "red", "yellow", or "#33cc8c".
Set fillcolor to the RGB color represented by the tuple of r, g, and b. Each of r, g, and b must be in the range 0..colormode, where colormode is either 1.0 or 255 (see colormode()).
Set fillcolor to the RGB color represented by r, g, and b. Each of r, g, and b must be in the range 0..colormode.
If turtleshape is a polygon, the interior of that polygon is drawn with the newly set fillcolor.
Return or set pencolor and fillcolor.
Several input formats are allowed. They use 0 to 3 arguments as follows:
Return the current pencolor and the current fillcolor as a pair of color specification strings or tuples as returned by pencolor() and fillcolor().
Inputs as in pencolor(), set both, fillcolor and pencolor, to the given value.
Equivalent to pencolor(colorstring1) and fillcolor(colorstring2) and analogously if the other input format is used.
If turtleshape is a polygon, outline and interior of that polygon is drawn with the newly set colors.
See also: Screen method colormode().
Return fillstate (True if filling, False else).
To be called just before drawing a shape to be filled.
Fill the shape drawn after the last call to begin_fill().
Whether or not overlap regions for self-intersecting polygons or multiple shapes are filled depends on the operating system graphics, type of overlap, and number of overlaps. For example, the Turtle star above may be either all yellow or have some white regions.
Delete the turtle’s drawings from the screen, re-center the turtle and set variables to the default values.
Delete the turtle’s drawings from the screen. Do not move turtle. State and position of the turtle as well as drawings of other turtles are not affected.
Write text - the string representation of arg - at the current turtle position according to align (“left”, “center” or “right”) and with the given font. If move is true, the pen is moved to the bottom-right corner of the text. By default, move is False.
Make the turtle invisible. It’s a good idea to do this while you’re in the middle of doing some complex drawing, because hiding the turtle speeds up the drawing observably.
Make the turtle visible.
Return True if the Turtle is shown, False if it’s hidden.
name – a string which is a valid shapename
Set turtle shape to shape with given name or, if name is not given, return name of current shape. Shape with name must exist in the TurtleScreen’s shape dictionary. Initially there are the following polygon shapes: “arrow”, “turtle”, “circle”, “square”, “triangle”, “classic”. To learn about how to deal with shapes see Screen method register_shape().
rmode – one of the strings “auto”, “user”, “noresize”
Set resizemode to one of the values: “auto”, “user”, “noresize”. If rmode is not given, return current resizemode. Different resizemodes have the following effects:
resizemode("user") is called by shapesize() when used with arguments.
Return or set the pen’s attributes x/y-stretchfactors and/or outline. Set resizemode to “user”. If and only if resizemode is set to “user”, the turtle will be displayed stretched according to its stretchfactors: stretch_wid is stretchfactor perpendicular to its orientation, stretch_len is stretchfactor in direction of its orientation, outline determines the width of the shapes’s outline.
shear – number (optional)
Set or return the current shearfactor. Shear the turtleshape according to the given shearfactor shear, which is the tangent of the shear angle. Do not change the turtle’s heading (direction of movement). If shear is not given: return the current shearfactor, i. e. the tangent of the shear angle, by which lines parallel to the heading of the turtle are sheared.
angle – a number
Rotate the turtleshape by angle from its current tilt-angle, but do not change the turtle’s heading (direction of movement).
angle – a number
Rotate the turtleshape to point in the direction specified by angle, regardless of its current tilt-angle. Do not change the turtle’s heading (direction of movement).
Deprecated since version 3.1.
angle – a number (optional)
Set or return the current tilt-angle. If angle is given, rotate the turtleshape to point in the direction specified by angle, regardless of its current tilt-angle. Do not change the turtle’s heading (direction of movement). If angle is not given: return the current tilt-angle, i. e. the angle between the orientation of the turtleshape and the heading of the turtle (its direction of movement).
Set or return the current transformation matrix of the turtle shape.
If none of the matrix elements are given, return the transformation matrix as a tuple of 4 elements. Otherwise set the given elements and transform the turtleshape according to the matrix consisting of first row t11, t12 and second row t21, t22. The determinant t11 * t22 - t12 * t21 must not be zero, otherwise an error is raised. Modify stretchfactor, shearfactor and tiltangle according to the given matrix.
Return the current shape polygon as tuple of coordinate pairs. This can be used to define a new shape or components of a compound shape.
Bind fun to mouse-click events on this turtle. If fun is None, existing bindings are removed. Example for the anonymous turtle, i.e. the procedural way:
Bind fun to mouse-button-release events on this turtle. If fun is None, existing bindings are removed.
Bind fun to mouse-move events on this turtle. If fun is None, existing bindings are removed.
Remark: Every sequence of mouse-move-events on a turtle is preceded by a mouse-click event on that turtle.
Subsequently, clicking and dragging the Turtle will move it across the screen thereby producing handdrawings (if pen is down).
Start recording the vertices of a polygon. Current turtle position is first vertex of polygon.
Stop recording the vertices of a polygon. Current turtle position is last vertex of polygon. This will be connected with the first vertex.
Return the last recorded polygon.
Create and return a clone of the turtle with same position, heading and turtle properties.
Return the Turtle object itself. Only reasonable use: as a function to return the “anonymous turtle”:
Return the TurtleScreen object the turtle is drawing on. TurtleScreen methods can then be called for that object.
size – an integer or None
Set or disable undobuffer. If size is an integer, an empty undobuffer of given size is installed. size gives the maximum number of turtle actions that can be undone by the undo() method/function. If size is None, the undobuffer is disabled.
Return number of entries in the undobuffer.
To use compound turtle shapes, which consist of several polygons of different color, you must use the helper class Shape explicitly as described below:
Add as many components to this object as desired, using the addcomponent() method.
For example:
Now add the Shape to the Screen’s shapelist and use it:
Note
The Shape class is used internally by the register_shape() method in different ways. The application programmer has to deal with the Shape class only when using compound shapes like shown above!
Most of the examples in this section refer to a TurtleScreen instance called screen.
args – a color string or three numbers in the range 0..colormode or a 3-tuple of such numbers
Set or return background color of the TurtleScreen.
picname – a string, name of a gif-file or "nopic", or None
Set background image or return name of current backgroundimage. If picname is a filename, set the corresponding image as background. If picname is "nopic", delete background image, if present. If picname is None, return the filename of the current backgroundimage.
Delete all drawings and all turtles from the TurtleScreen. Reset the now empty TurtleScreen to its initial state: white background, no background image, no event bindings and tracing on.
Note
This TurtleScreen method is available as a global function only under the name clearscreen. The global function clear is a different one derived from the Turtle method clear.
Reset all Turtles on the Screen to their initial state.
Note
This TurtleScreen method is available as a global function only under the name resetscreen. The global function reset is another one derived from the Turtle method reset.
If no arguments are given, return current (canvaswidth, canvasheight). Else resize the canvas the turtles are drawing on. Do not alter the drawing window. To observe hidden parts of the canvas, use the scrollbars. With this method, one can make visible those parts of a drawing which were outside the canvas before.
e.g. to search for an erroneously escaped turtle ;-)
Set up user-defined coordinate system and switch to mode “world” if necessary. This performs a screen.reset(). If mode “world” is already active, all drawings are redrawn according to the new coordinates.
ATTENTION: in user-defined coordinate systems angles may appear distorted.
delay – positive integer
Set or return the drawing delay in milliseconds. (This is approximately the time interval between two consecutive canvas updates.) The longer the drawing delay, the slower the animation.
Optional argument:
Turn turtle animation on/off and set delay for update drawings. If n is given, only each n-th regular screen update is really performed. (Can be used to accelerate the drawing of complex graphics.) When called without arguments, returns the currently stored value of n. Second argument sets delay value (see delay()).
Perform a TurtleScreen update. To be used when tracer is turned off.
See also the RawTurtle/Turtle method speed().
Set focus on TurtleScreen (in order to collect key-events). Dummy arguments are provided in order to be able to pass listen() to the onclick method.
Bind fun to key-release event of key. If fun is None, event bindings are removed. Remark: in order to be able to register key-events, TurtleScreen must have the focus. (See method listen().)
Bind fun to key-press event of key if key is given, or to any key-press-event if no key is given. Remark: in order to be able to register key-events, TurtleScreen must have focus. (See method listen().)
Bind fun to mouse-click events on this screen. If fun is None, existing bindings are removed.
Example for a TurtleScreen instance named screen and a Turtle instance named turtle:
Note
This TurtleScreen method is available as a global function only under the name onscreenclick. The global function onclick is another one derived from the Turtle method onclick.
Install a timer that calls fun after t milliseconds.
Starts event loop - calling Tkinter’s mainloop function. Must be the last statement in a turtle graphics program. Must not be used if a script is run from within IDLE in -n mode (No subprocess) - for interactive use of turtle graphics.
Pop up a dialog window for input of a string. Parameter title is the title of the dialog window, prompt is a text mostly describing what information to input. Return the string input. If the dialog is canceled, return None.
Pop up a dialog window for input of a number. title is the title of the dialog window, prompt is a text mostly describing what numerical information to input. default: default value, minval: minimum value for input, maxval: maximum value for input The number input must be in the range minval .. maxval if these are given. If not, a hint is issued and the dialog remains open for correction. Return the number input. If the dialog is canceled, return None.
mode – one of the strings “standard”, “logo” or “world”
Set turtle mode (“standard”, “logo” or “world”) and perform reset. If mode is not given, current mode is returned.
Mode “standard” is compatible with old turtle. Mode “logo” is compatible with most Logo turtle graphics. Mode “world” uses user-defined “world coordinates”. Attention: in this mode angles appear distorted if x/y unit-ratio doesn’t equal 1.
Mode
Initial turtle heading
positive angles
“standard”
to the right (east)
counterclockwise
“logo”
upward (north)
clockwise
cmode – one of the values 1.0 or 255
Return the colormode or set it to 1.0 or 255. Subsequently r, g, b values of color triples have to be in the range 0..cmode.
Return the Canvas of this TurtleScreen. Useful for insiders who know what to do with a Tkinter Canvas.
Return a list of names of all currently available turtle shapes.
There are three different ways to call this function:
name is the name of a gif-file and shape is None: Install the corresponding image shape.
Note
Image shapes do not rotate when turning the turtle, so they do not display the heading of the turtle!
name is an arbitrary string and shape is a tuple of pairs of coordinates: Install the corresponding polygon shape.
Add a turtle shape to TurtleScreen’s shapelist. Only thusly registered shapes can be used by issuing the command shape(shapename).
Return the list of turtles on the screen.
Return the height of the turtle window.
Return the width of the turtle window.
Shut the turtlegraphics window.
Bind bye() method to mouse clicks on the Screen.
If the value “using_IDLE” in the configuration dictionary is False (default value), also enter mainloop. Remark: If IDLE with the -n switch (no subprocess) is used, this value should be set to True in turtle.cfg. In this case IDLE’s own mainloop is active also for the client script.
Set the size and position of the main window. Default values of arguments are stored in the configuration dictionary and can be changed via a turtle.cfg file.
titlestring – a string that is shown in the titlebar of the turtle graphics window
Set title of turtle window to titlestring.
canvas – a tkinter.Canvas, a ScrolledCanvas or a TurtleScreen
Create a turtle. The turtle has all methods described above as “methods of Turtle/RawTurtle”.
Subclass of RawTurtle, has the same interface but draws on a default Screen object created automatically when needed for the first time.
cv – a tkinter.Canvas
Provides screen oriented methods like setbg() etc. that are described above.
Subclass of TurtleScreen, with four methods added.
master – some Tkinter widget to contain the ScrolledCanvas, i.e. a Tkinter-canvas with scrollbars added
Used by class Screen, which thus automatically provides a ScrolledCanvas as playground for the turtles.
type_ – one of the strings “polygon”, “image”, “compound”
Data structure modeling shapes. The pair (type_, data) must follow this specification:
type_
data
“polygon”
a polygon-tuple, i.e. a tuple of pairs of coordinates
“image”
an image (in this form only used internally!)
“compound”
None (a compound shape has to be constructed using the addcomponent() method)
Example:
See Compound shapes.
A two-dimensional vector class, used as a helper class for implementing turtle graphics. May be useful for turtle graphics programs too. Derived from tuple, so a vector is a tuple!
Provides (for a, b vectors, k number):
The public methods of the Screen and Turtle classes are documented extensively via docstrings. So these can be used as online-help via the Python help facilities:
Calling help() on methods or functions displays the docstrings:
The docstrings of the functions which are derived from methods have a modified form:
These modified docstrings are created automatically together with the function definitions that are derived from the methods at import time.
There is a utility to create a dictionary the keys of which are the method names and the values of which are the docstrings of the public methods of the classes Screen and Turtle.
filename – a string, used as filename
Create and write docstring-dictionary to a Python script with the given filename. This function has to be called explicitly (it is not used by the turtle graphics classes). The docstring dictionary will be written to the Python script filename.py. It is intended to serve as a template for translation of the docstrings into different languages.
If you (or your students) want to use turtle with online help in your native language, you have to translate the docstrings and save the resulting file as e.g. turtle_docstringdict_german.py.
If you have an appropriate entry in your turtle.cfg file this dictionary will be read in at import time and will replace the original English docstrings.
At the time of this writing there are docstring dictionaries in German and in Italian. (Requests please to glingl@aon.at.)
The built-in default configuration mimics the appearance and behaviour of the old turtle module in order to retain best possible compatibility with it.
If you want to use a different configuration which better reflects the features of this module or which better fits to your needs, e.g. for use in a classroom, you can prepare a configuration file turtle.cfg which will be read at import time and modify the configuration according to its settings.
The built in configuration would correspond to the following turtle.cfg:
Short explanation of selected entries:
There can be a turtle.cfg file in the directory where turtle is stored and an additional one in the current working directory. The latter will override the settings of the first one.
The Lib/turtledemo directory contains a turtle.cfg file. You can study it as an example and see its effects when running the demos (preferably not from within the demo-viewer).
The turtledemo package includes a set of demo scripts. These scripts can be run and viewed using the supplied demo viewer as follows:
Alternatively, you can run the demo scripts individually. For example,
The turtledemo package directory contains:
The demo scripts are:
Name
Description
Features
bytedesign
complex classical turtle graphics pattern
tracer(), delay, update()
chaos
graphs Verhulst dynamics, shows that computer’s computations can generate results sometimes against the common sense expectations
world coordinates
clock
analog clock showing time of your computer
turtles as clock’s hands, ontimer
colormixer
experiment with r, g, b
ondrag()
forest
3 breadth-first trees
randomization
fractalcurves
Hilbert & Koch curves
recursion
lindenmayer
ethnomathematics (indian kolams)
L-System
minimal_hanoi
Towers of Hanoi
Rectangular Turtles as Hanoi discs (shape, shapesize)
nim
play the classical nim game with three heaps of sticks against the computer.
turtles as nimsticks, event driven (mouse, keyboard)
paint
super minimalistic drawing program
onclick()
peace
elementary
turtle: appearance and animation
penrose
aperiodic tiling with kites and darts
stamp()
planet_and_moon
simulation of gravitational system
compound shapes, Vec2D
round_dance
dancing turtles rotating pairwise in opposite direction
compound shapes, clone shapesize, tilt, get_shapepoly, update
sorting_animate
visual demonstration of different sorting methods
simple alignment, randomization
tree
a (graphical) breadth first tree (using generators)
clone()
two_canvases
simple design
turtles on two canvases
wikipedia
a pattern from the wikipedia article on turtle graphics
clone(), undo()
yinyang
another elementary example
circle()
Have fun!


There are three different ways to call this function:
name is the name of a gif-file and shape is None: Install the corresponding image shape.
Note
Image shapes do not rotate when turning the turtle, so they do not display the heading of the turtle!
name is an arbitrary string and shape is a tuple of pairs of coordinates: Install the corresponding polygon shape.
Add a turtle shape to TurtleScreen’s shapelist. Only thusly registered shapes can be used by issuing the command shape(shapename).


distance – a number
Move the turtle backward by distance, opposite to the direction the turtle is headed. Do not change the turtle’s heading.


To be called just before drawing a shape to be filled.


Start recording the vertices of a polygon. Current turtle position is first vertex of polygon.


args – a color string or three numbers in the range 0..colormode or a 3-tuple of such numbers
Set or return background color of the TurtleScreen.


picname – a string, name of a gif-file or "nopic", or None
Set background image or return name of current backgroundimage. If picname is a filename, set the corresponding image as background. If picname is "nopic", delete background image, if present. If picname is None, return the filename of the current backgroundimage.


Draw a circle with given radius. The center is radius units left of the turtle; extent – an angle – determines which part of the circle is drawn. If extent is not given, draw the entire circle. If extent is not a full circle, one endpoint of the arc is the current pen position. Draw the arc in counterclockwise direction if radius is positive, otherwise in clockwise direction. Finally the direction of the turtle is changed by the amount of extent.
As the circle is approximated by an inscribed regular polygon, steps determines the number of steps to use. If not given, it will be calculated automatically. May be used to draw regular polygons.


Delete all drawings and all turtles from the TurtleScreen. Reset the now empty TurtleScreen to its initial state: white background, no background image, no event bindings and tracing on.
Note
This TurtleScreen method is available as a global function only under the name clearscreen. The global function clear is a different one derived from the Turtle method clear.


stampid – an integer, must be return value of previous stamp() call
Delete stamp with given stampid.


n – an integer (or None)
Delete all or first/last n of turtle’s stamps. If n is None, delete all stamps, if n > 0 delete first n stamps, else if n < 0 delete last n stamps.


Create and return a clone of the turtle with same position, heading and turtle properties.


Return or set pencolor and fillcolor.
Several input formats are allowed. They use 0 to 3 arguments as follows:
Return the current pencolor and the current fillcolor as a pair of color specification strings or tuples as returned by pencolor() and fillcolor().
Inputs as in pencolor(), set both, fillcolor and pencolor, to the given value.
Equivalent to pencolor(colorstring1) and fillcolor(colorstring2) and analogously if the other input format is used.
If turtleshape is a polygon, outline and interior of that polygon is drawn with the newly set colors.


cmode – one of the values 1.0 or 255
Return the colormode or set it to 1.0 or 255. Subsequently r, g, b values of color triples have to be in the range 0..cmode.


fullcircle – a number
Set angle measurement units, i.e. set number of “degrees” for a full circle. Default value is 360 degrees.


delay – positive integer
Set or return the drawing delay in milliseconds. (This is approximately the time interval between two consecutive canvas updates.) The longer the drawing delay, the slower the animation.
Optional argument:


Return the distance from the turtle to (x,y), the given vector, or the given other turtle, in turtle step units.


Starts event loop - calling Tkinter’s mainloop function. Must be the last statement in a turtle graphics program. Must not be used if a script is run from within IDLE in -n mode (No subprocess) - for interactive use of turtle graphics.


Draw a circular dot with diameter size, using color. If size is not given, the maximum of pensize+4 and 2*pensize is used.


Pull the pen down – drawing when moving.


Fill the shape drawn after the last call to begin_fill().
Whether or not overlap regions for self-intersecting polygons or multiple shapes are filled depends on the operating system graphics, type of overlap, and number of overlaps. For example, the Turtle star above may be either all yellow or have some white regions.


Stop recording the vertices of a polygon. Current turtle position is last vertex of polygon. This will be connected with the first vertex.


Bind bye() method to mouse clicks on the Screen.
If the value “using_IDLE” in the configuration dictionary is False (default value), also enter mainloop. Remark: If IDLE with the -n switch (no subprocess) is used, this value should be set to True in turtle.cfg. In this case IDLE’s own mainloop is active also for the client script.


distance – a number (integer or float)
Move the turtle forward by the specified distance, in the direction the turtle is headed.


Return or set the fillcolor.
Four input formats are allowed:
Return the current fillcolor as color specification string, possibly in tuple format (see example). May be used as input to another color/pencolor/fillcolor call.
Set fillcolor to colorstring, which is a Tk color specification string, such as "red", "yellow", or "#33cc8c".
Set fillcolor to the RGB color represented by the tuple of r, g, and b. Each of r, g, and b must be in the range 0..colormode, where colormode is either 1.0 or 255 (see colormode()).
Set fillcolor to the RGB color represented by r, g, and b. Each of r, g, and b must be in the range 0..colormode.
If turtleshape is a polygon, the interior of that polygon is drawn with the newly set fillcolor.


Return fillstate (True if filling, False else).


Return the Canvas of this TurtleScreen. Useful for insiders who know what to do with a Tkinter Canvas.


Return the Turtle object itself. Only reasonable use: as a function to return the “anonymous turtle”:


Return the TurtleScreen object the turtle is drawing on. TurtleScreen methods can then be called for that object.


Return a list of names of all currently available turtle shapes.


Return the current shape polygon as tuple of coordinate pairs. This can be used to define a new shape or components of a compound shape.


If y is None, x must be a pair of coordinates or a Vec2D (e.g. as returned by pos()).
Move turtle to an absolute position. If the pen is down, draw line. Do not change the turtle’s orientation.


Return the turtle’s current heading (value depends on the turtle mode, see mode()).


Make the turtle invisible. It’s a good idea to do this while you’re in the middle of doing some complex drawing, because hiding the turtle speeds up the drawing observably.


Move turtle to the origin – coordinates (0,0) – and set its heading to its start-orientation (which depends on the mode, see mode()).


Return True if pen is down, False if it’s up.


Return True if the Turtle is shown, False if it’s hidden.


angle – a number (integer or float)
Turn turtle left by angle units. (Units are by default degrees, but can be set via the degrees() and radians() functions.) Angle orientation depends on the turtle mode, see mode().


Set focus on TurtleScreen (in order to collect key-events). Dummy arguments are provided in order to be able to pass listen() to the onclick method.


Starts event loop - calling Tkinter’s mainloop function. Must be the last statement in a turtle graphics program. Must not be used if a script is run from within IDLE in -n mode (No subprocess) - for interactive use of turtle graphics.


mode – one of the strings “standard”, “logo” or “world”
Set turtle mode (“standard”, “logo” or “world”) and perform reset. If mode is not given, current mode is returned.
Mode “standard” is compatible with old turtle. Mode “logo” is compatible with most Logo turtle graphics. Mode “world” uses user-defined “world coordinates”. Attention: in this mode angles appear distorted if x/y unit-ratio doesn’t equal 1.
Mode
Initial turtle heading
positive angles
“standard”
to the right (east)
counterclockwise
“logo”
upward (north)
clockwise


Pop up a dialog window for input of a number. title is the title of the dialog window, prompt is a text mostly describing what numerical information to input. default: default value, minval: minimum value for input, maxval: maximum value for input The number input must be in the range minval .. maxval if these are given. If not, a hint is issued and the dialog remains open for correction. Return the number input. If the dialog is canceled, return None.


Bind fun to mouse-click events on this screen. If fun is None, existing bindings are removed.
Example for a TurtleScreen instance named screen and a Turtle instance named turtle:
Note
This TurtleScreen method is available as a global function only under the name onscreenclick. The global function onclick is another one derived from the Turtle method onclick.


Bind fun to mouse-move events on this turtle. If fun is None, existing bindings are removed.
Remark: Every sequence of mouse-move-events on a turtle is preceded by a mouse-click event on that turtle.
Subsequently, clicking and dragging the Turtle will move it across the screen thereby producing handdrawings (if pen is down).


Bind fun to key-release event of key. If fun is None, event bindings are removed. Remark: in order to be able to register key-events, TurtleScreen must have the focus. (See method listen().)


Bind fun to key-press event of key if key is given, or to any key-press-event if no key is given. Remark: in order to be able to register key-events, TurtleScreen must have focus. (See method listen().)


Bind fun to mouse-button-release events on this turtle. If fun is None, existing bindings are removed.


Install a timer that calls fun after t milliseconds.


Pull the pen down – drawing when moving.


Return or set the pen’s attributes in a “pen-dictionary” with the following key/value pairs:
This dictionary can be used as argument for a subsequent call to pen() to restore the former pen-state. Moreover one or more of these attributes can be provided as keyword-arguments. This can be used to set several pen attributes in one statement.


Return or set the pencolor.
Four input formats are allowed:
Return the current pencolor as color specification string or as a tuple (see example). May be used as input to another color/pencolor/fillcolor call.
Set pencolor to colorstring, which is a Tk color specification string, such as "red", "yellow", or "#33cc8c".
Set pencolor to the RGB color represented by the tuple of r, g, and b. Each of r, g, and b must be in the range 0..colormode, where colormode is either 1.0 or 255 (see colormode()).
Set pencolor to the RGB color represented by r, g, and b. Each of r, g, and b must be in the range 0..colormode.
If turtleshape is a polygon, the outline of that polygon is drawn with the newly set pencolor.


width – a positive number
Set the line thickness to width or return it. If resizemode is set to “auto” and turtleshape is a polygon, that polygon is drawn with the same line thickness. If no argument is given, the current pensize is returned.


Pull the pen up – no drawing when moving.


Return the turtle’s current location (x,y) (as a Vec2D vector).


Set the angle measurement units to radians. Equivalent to degrees(2*math.pi).


canvas – a tkinter.Canvas, a ScrolledCanvas or a TurtleScreen
Create a turtle. The turtle has all methods described above as “methods of Turtle/RawTurtle”.


There are three different ways to call this function:
name is the name of a gif-file and shape is None: Install the corresponding image shape.
Note
Image shapes do not rotate when turning the turtle, so they do not display the heading of the turtle!
name is an arbitrary string and shape is a tuple of pairs of coordinates: Install the corresponding polygon shape.
Add a turtle shape to TurtleScreen’s shapelist. Only thusly registered shapes can be used by issuing the command shape(shapename).


Reset all Turtles on the Screen to their initial state.
Note
This TurtleScreen method is available as a global function only under the name resetscreen. The global function reset is another one derived from the Turtle method reset.


rmode – one of the strings “auto”, “user”, “noresize”
Set resizemode to one of the values: “auto”, “user”, “noresize”. If rmode is not given, return current resizemode. Different resizemodes have the following effects:
resizemode("user") is called by shapesize() when used with arguments.


angle – a number (integer or float)
Turn turtle right by angle units. (Units are by default degrees, but can be set via the degrees() and radians() functions.) Angle orientation depends on the turtle mode, see mode().


Subclass of TurtleScreen, with four methods added.


If no arguments are given, return current (canvaswidth, canvasheight). Else resize the canvas the turtles are drawing on. Do not alter the drawing window. To observe hidden parts of the canvas, use the scrollbars. With this method, one can make visible those parts of a drawing which were outside the canvas before.
e.g. to search for an erroneously escaped turtle ;-)


master – some Tkinter widget to contain the ScrolledCanvas, i.e. a Tkinter-canvas with scrollbars added
Used by class Screen, which thus automatically provides a ScrolledCanvas as playground for the turtles.


to_angle – a number (integer or float)
Set the orientation of the turtle to to_angle. Here are some common directions in degrees:
standard mode
logo mode
0 - east
0 - north
90 - north
90 - east
180 - west
180 - south
270 - south
270 - west


If y is None, x must be a pair of coordinates or a Vec2D (e.g. as returned by pos()).
Move turtle to an absolute position. If the pen is down, draw line. Do not change the turtle’s orientation.


angle – a number
Rotate the turtleshape to point in the direction specified by angle, regardless of its current tilt-angle. Do not change the turtle’s heading (direction of movement).
Deprecated since version 3.1.


size – an integer or None
Set or disable undobuffer. If size is an integer, an empty undobuffer of given size is installed. size gives the maximum number of turtle actions that can be undone by the undo() method/function. If size is None, the undobuffer is disabled.


Set the size and position of the main window. Default values of arguments are stored in the configuration dictionary and can be changed via a turtle.cfg file.


Set up user-defined coordinate system and switch to mode “world” if necessary. This performs a screen.reset(). If mode “world” is already active, all drawings are redrawn according to the new coordinates.
ATTENTION: in user-defined coordinate systems angles may appear distorted.


x – a number (integer or float)
Set the turtle’s first coordinate to x, leave second coordinate unchanged.


y – a number (integer or float)
Set the turtle’s second coordinate to y, leave first coordinate unchanged.


type_ – one of the strings “polygon”, “image”, “compound”
Data structure modeling shapes. The pair (type_, data) must follow this specification:
type_
data
“polygon”
a polygon-tuple, i.e. a tuple of pairs of coordinates
“image”
an image (in this form only used internally!)
“compound”
None (a compound shape has to be constructed using the addcomponent() method)
Example:
See Compound shapes.


name – a string which is a valid shapename
Set turtle shape to shape with given name or, if name is not given, return name of current shape. Shape with name must exist in the TurtleScreen’s shape dictionary. Initially there are the following polygon shapes: “arrow”, “turtle”, “circle”, “square”, “triangle”, “classic”. To learn about how to deal with shapes see Screen method register_shape().


Return or set the pen’s attributes x/y-stretchfactors and/or outline. Set resizemode to “user”. If and only if resizemode is set to “user”, the turtle will be displayed stretched according to its stretchfactors: stretch_wid is stretchfactor perpendicular to its orientation, stretch_len is stretchfactor in direction of its orientation, outline determines the width of the shapes’s outline.


Set or return the current transformation matrix of the turtle shape.
If none of the matrix elements are given, return the transformation matrix as a tuple of 4 elements. Otherwise set the given elements and transform the turtleshape according to the matrix consisting of first row t11, t12 and second row t21, t22. The determinant t11 * t22 - t12 * t21 must not be zero, otherwise an error is raised. Modify stretchfactor, shearfactor and tiltangle according to the given matrix.


shear – number (optional)
Set or return the current shearfactor. Shear the turtleshape according to the given shearfactor shear, which is the tangent of the shear angle. Do not change the turtle’s heading (direction of movement). If shear is not given: return the current shearfactor, i. e. the tangent of the shear angle, by which lines parallel to the heading of the turtle are sheared.


speed – an integer in the range 0..10 or a speedstring (see below)
Set the turtle’s speed to an integer value in the range 0..10. If no argument is given, return current speed.
If input is a number greater than 10 or smaller than 0.5, speed is set to 0. Speedstrings are mapped to speedvalues as follows:
Speeds from 1 to 10 enforce increasingly faster animation of line drawing and turtle turning.
Attention: speed = 0 means that no animation takes place. forward/back makes turtle jump and likewise left/right make the turtle turn instantly.


Stamp a copy of the turtle shape onto the canvas at the current turtle position. Return a stamp_id for that stamp, which can be used to delete it by calling clearstamp(stamp_id).


Pop up a dialog window for input of a string. Parameter title is the title of the dialog window, prompt is a text mostly describing what information to input. Return the string input. If the dialog is canceled, return None.


angle – a number
Rotate the turtleshape by angle from its current tilt-angle, but do not change the turtle’s heading (direction of movement).


angle – a number (optional)
Set or return the current tilt-angle. If angle is given, rotate the turtleshape to point in the direction specified by angle, regardless of its current tilt-angle. Do not change the turtle’s heading (direction of movement). If angle is not given: return the current tilt-angle, i. e. the angle between the orientation of the turtleshape and the heading of the turtle (its direction of movement).


titlestring – a string that is shown in the titlebar of the turtle graphics window
Set title of turtle window to titlestring.


Return the angle between the line from turtle position to position specified by (x,y), the vector or the other turtle. This depends on the turtle’s start orientation which depends on the mode - “standard”/”world” or “logo”.


Turn turtle animation on/off and set delay for update drawings. If n is given, only each n-th regular screen update is really performed. (Can be used to accelerate the drawing of complex graphics.) When called without arguments, returns the currently stored value of n. Second argument sets delay value (see delay()).


Subclass of RawTurtle, has the same interface but draws on a default Screen object created automatically when needed for the first time.


Return the list of turtles on the screen.


cv – a tkinter.Canvas
Provides screen oriented methods like setbg() etc. that are described above.


Undo (repeatedly) the last turtle action(s). Number of available undo actions is determined by the size of the undobuffer.


Return number of entries in the undobuffer.


Pull the pen up – no drawing when moving.


Perform a TurtleScreen update. To be used when tracer is turned off.


A two-dimensional vector class, used as a helper class for implementing turtle graphics. May be useful for turtle graphics programs too. Derived from tuple, so a vector is a tuple!
Provides (for a, b vectors, k number):


width – a positive number
Set the line thickness to width or return it. If resizemode is set to “auto” and turtleshape is a polygon, that polygon is drawn with the same line thickness. If no argument is given, the current pensize is returned.


Write text - the string representation of arg - at the current turtle position according to align (“left”, “center” or “right”) and with the given font. If move is true, the pen is moved to the bottom-right corner of the text. By default, move is False.


filename – a string, used as filename
Create and write docstring-dictionary to a Python script with the given filename. This function has to be called explicitly (it is not used by the turtle graphics classes). The docstring dictionary will be written to the Python script filename.py. It is intended to serve as a template for translation of the docstrings into different languages.


With one argument, return the type of an object. The return value is a type object and generally the same object as returned by object.__class__.
The isinstance() built-in function is recommended for testing the type of an object, because it takes subclasses into account.
With three arguments, return a new type object. This is essentially a dynamic form of the class statement. The name string is the class name and becomes the __name__ attribute. The bases tuple contains the base classes and becomes the __bases__ attribute; if empty, object, the ultimate base of all classes, is added. The dict dictionary contains attribute and method definitions for the class body; it may be copied or wrapped before becoming the __dict__ attribute. The following two statements create identical type objects:
See also Type Objects.
Keyword arguments provided to the three argument form are passed to the appropriate metaclass machinery (usually __init_subclass__()) in the same way that keywords in a class definition (besides metaclass) would.
See also Customizing class creation.
Changed in version 3.6: Subclasses of type which don’t override type.__new__ may no longer use the one-argument form to get the type of an object.


Raised when an operation or function is applied to an object of inappropriate type. The associated value is a string giving details about the type mismatch.
This exception may be raised by user code to indicate that an attempted operation on an object is not supported, and is not meant to be. If an object is meant to support a given operation but has not yet provided an implementation, NotImplementedError is the proper exception to raise.
Passing arguments of the wrong type (e.g. passing a list when an int is expected) should result in a TypeError, but passing arguments with the wrong value (e.g. a number outside expected boundaries) should result in a ValueError.