*args and **kwargs in Python - GeeksforGeeks

15 Dec, 2021
In Python, we can pass a variable number of arguments to a function using special symbols. There are two special symbols:
Special Symbols Used for passing arguments:-
1.)*args (Non-Keyword Arguments)
2.)**kwargs (Keyword Arguments)
Note: “We use the “wildcard” or “*” notation like this – *args OR **kwargs – as our function’s argument when we have doubts about the number of  arguments we should pass in a function.” 
1.) *args
The special syntax *args in function definitions in python is used to pass a variable number of arguments to a function. It is used to pass a non-key worded, variable-length argument list. 
The syntax is to use the symbol * to take in a variable number of arguments; by convention, it is often used with the word args.
What *args allows you to do is take in more arguments than the number of formal arguments that you previously defined. With *args, any number of extra arguments can be tacked on to your current formal parameters (including zero extra arguments).
For example : we want to make a multiply function that takes any number of arguments and able to multiply them all together. It can be done using *args.
Using the *, the variable that we associate with the * becomes an iterable meaning you can do things like iterate over it, run some higher-order functions such as map and filter, etc. 
python3
# Python program to illustrate # *args for variable number of argumentsdef myFun(*argv):    for arg in argv:        print (arg)   myFun('Hello', 'Welcome', 'to', 'GeeksforGeeks')
Hello
Welcome
to
GeeksforGeeks
 
Python3
# Python program to illustrate# *args with first extra argumentdef myFun(arg1, *argv):    print ("First argument :", arg1)    for arg in argv:        print("Next argument through *argv :", arg) myFun('Hello', 'Welcome', 'to', 'GeeksforGeeks')
First argument : Hello
Next argument through *argv : Welcome
Next argument through *argv : to
Next argument through *argv : GeeksforGeeks
 
 
2.)**kwargs
The special syntax **kwargs in function definitions in python is used to pass a keyworded, variable-length argument list. We use the name kwargs with the double star. The reason is because the double star allows us to pass through keyword arguments (and any number of them).
A keyword argument is where you provide a name to the variable as you pass it into the function.
One can think of the kwargs as being a dictionary that maps each keyword to the value that we pass alongside it. That is why when we iterate over the kwargs there doesn’t seem to be any order in which they were printed out.
Example for usage of **kwargs: 
python
# Python program to illustrate # *kwargs for variable number of keyword arguments def myFun(**kwargs):    for key, value in kwargs.items():        print ("%s == %s" %(key, value)) # Driver codemyFun(first ='Geeks', mid ='for', last='Geeks')   
last == Geeks
mid == for
first == Geeks
 
python
# Python program to illustrate  **kwargs for# variable number of keyword arguments with# one extra argument. def myFun(arg1, **kwargs):    for key, value in kwargs.items():        print ("%s == %s" %(key, value)) # Driver codemyFun("Hi", first ='Geeks', mid ='for', last='Geeks')   
last == Geeks
mid == for
first == Geeks
 
Example: 
python3
def myFun(arg1, arg2, arg3):    print("arg1:", arg1)    print("arg2:", arg2)    print("arg3:", arg3)     # Now we can use *args or **kwargs to# pass arguments to this function :args = ("Geeks", "for", "Geeks")myFun(*args) kwargs = {"arg1" : "Geeks", "arg2" : "for", "arg3" : "Geeks"}myFun(**kwargs)
arg1: Geeks
arg2: for
arg3: Geeks
arg1: Geeks
arg2: for
arg3: Geeks
 
Example: 
python3
def myFun(*args,**kwargs):    print("args: ", args)    print("kwargs: ", kwargs)  # Now we can use both *args ,**kwargs# to pass arguments to this function :myFun('geeks','for','geeks',first="Geeks",mid="for",last="Geeks")
args: ('geeks', 'for', 'geeks')
kwargs {'first': 'Geeks', 'mid': 'for', 'last': 'Geeks'}
 
This article is contributed by Kishlay Verma. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. 
DivyaVishwakarma
abhijithonline
pulkitagarwal03pulkit
markevogt
rkbhola5
Python-Functions
Python
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Read JSON file using Python
Adding new column to existing DataFrame in Pandas
Python map() function
How to get column names in Pandas dataframe
Read a file line by line in Python
How to Install PIP on Windows ?
Enumerate() in Python
Different ways to create Pandas Dataframe
Iterate over a list in Python
Python String | replace()