Ternary operators 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 to test 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:**# Program to demonstrate conditional operator a, b = 10, 20 # Copy value of a in min if a < b else copy b min = a if a < b else b print(min)

**Output:**10**Direct Method by using tuples, Dictionary and lambda**# Python program to demonstrate ternary operator a, b = 10, 20 # Use tuple for selecting an item print( (b, a) [a < b] ) # Use Dictionary for selecting an item print({True: a, False: b} [a < b]) # lamda is more efficient than above two methods # because in lambda we are assure that # only one expression will be evaluated unlike in # tuple and Dictionary print((lambda: b, lambda: a)[a < b]())

Output: 10 10 10

**Ternary operator can be written as nested if-else:**# Python program to demonstrate nested ternary operator a, 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")

*Above approach can be written as:*# Python program to demonstrate nested ternary operator a, 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

Important Points:

- 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 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 :**

# Program to demonstrate conditional operator a, 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 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 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 contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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