Ternary Operator in Python

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 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

# Python program to demonstrate ternary operator a, 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 print print( (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 Dictionary print((lambda: b, lambda: a)[a < b]())

Output:

10
10
10

Time Complexity: O(1)

Auxiliary Space: O(1)

• Ternary operator can be written as nested if-else:

• Python

# 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")

Time Complexity: O(1)

Auxiliary Space: O(1)

The above approach can be written as: 
 

• Python

# 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

Time Complexity: O(1)

Auxiliary Space: O(1)

• To use print function in ternary operator be like:- 

Example: Find the Larger number among 2 using ternary operator in python3

• Python3

a=5 b=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

Time Complexity: O(1)

Auxiliary Space: O(1)