Ternary Operator in Python

24 May, 2022
Ternary operators are also known as conditional expressions are operators that evaluate something based on a condition being true or false. It was added to Python in version 2.5. It simply allows testing a condition in a single line replacing the multiline if-else making the code compact. 
Syntax : 
[on_true] if [expression] else [on_false] 
Simple Method to use ternary operator:
Python
# Program to demonstrate conditional operatora, b = 10, 20  # Copy value of a in min if a < b else copy bmin = a if a < b else b  print(min)
Output: 
10
Direct Method by using tuples, Dictionary, and lambda
Python
# Python program to demonstrate ternary operatora, b = 10, 20  # Use tuple for selecting an item# (if_test_false,if_test_true)[test]# if [a<b] is true it return 1, so element with 1 index will print# else if [a<b] is false it return 0, so element with 0 index will printprint( (b, a) [a < b] )  # Use Dictionary for selecting an item# if [a < b] is true then value of True key will print# else if [a<b] is false then value of False key will print print({True: a, False: b} [a < b])  # lambda is more efficient than above two methods# because in lambda  we are assure that# only one expression will be evaluated unlike in# tuple and Dictionaryprint((lambda: b, lambda: a)[a < b]())
Output:
10
10
10
Ternary operator can be written as nested if-else:
Python
# Python program to demonstrate nested ternary operatora, b = 10, 20  print ("Both a and b are equal" if a == b else "a is greater than b"        if a > b else "b is greater than a")
The above approach can be written as:  
Python
# Python program to demonstrate nested ternary operatora, b = 10, 20  if a != b:    if a > b:        print("a is greater than b")    else:        print("b is greater than a")else:    print("Both a and b are equal")
Output:
 b is greater than a
To use print function in ternary operator be like:- 
Example: Find the Larger number among 2 using ternary operator in python3
Python3
a=5b=7  # [statement_on_True] if [condition] else [statement_on_false]   print(a,"is greater") if (a>b) else print(b,"is Greater")
Output:
7 is Greater
First the given condition is evaluated (a < b), then either a or b is returned based on the Boolean value returned by the condition
Order of the arguments in the operator is different from other languages like C/C++ (See C/C++ ternary operators).
Conditional expressions have the lowest priority amongst all Python operations.
Method used prior to 2.5 when the ternary operator was not present In an expression like the one given below, the interpreter checks for the expression if this is true then on_true is evaluated, else the on_false is evaluated. 
Syntax : 
'''When condition becomes true, expression [on_false]
   is not executed and value of "True and [on_true]"
   is returned.  Else value of "False or [on_false]"
   is returned.
   Note that "True and x" is equal to x. 
   And "False or x" is equal to x. '''
[expression] and [on_true] or [on_false] 
Example : 
Python
      # Program to demonstrate conditional operatora, b = 10, 20  # If a is less than b, then a is assigned# else b is assigned (Note : it doesn't # work if a is 0.min = a < b and a or b  print(min)
Output:
10
Note : The only drawback of this method is that on_true must not be zero or False. If this happens on_false will be evaluated always. The reason for that is if the expression is true, the interpreter will check for the on_true, if that will be zero or false, that will force the interpreter to check for on_false to give the final result of the whole expression.
This article is contributed by Mayank Rawat and improved by Shubham Bansal. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.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. 
nsuman35
tanyatomar98
rockysharaf
varshagumber28
germanshephered48
surinderdawra388
Python
School Programming
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Read JSON file using Python
Python map() function
Adding new column to existing DataFrame in Pandas
How to get column names in Pandas dataframe
Different ways to create Pandas Dataframe
Reverse a string in Java
Arrays in C/C++
Object Oriented Programming in C++
Interfaces in Java
Inheritance in C++