Python Ternary Conditional Operator

By Hafeezul Kareem | Updated: October 16, 2019

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Tags: python ternary operator tuple

This article shows you how to write Python ternary operator, also called conditional expressions.

<expression1> if <condition> else <expression2>

expression1 will be evaluated if the condition is true, otherwise expression2 will be evaluated.

1. Ternary Operator

1.1 This example will print whether a number is odd or even.

n = 5
print("Even") if n % 2 == 0 else print("Odd")

Output

Odd

if n = 2

Even

1.2 Can’t assign to conditional expression.

## we can't use syntax as follows
a = 5 if True else a = 6

Output

      File "<ipython-input-4-66113f0b2850>", line 2
        a = 5 if True else a = 6
           ^
    SyntaxError: can't assign to conditional expression

Instead, assign value to a variable as follows.

## we can use it as follows
a = 5 if False else 6
print(a)

Output

6

2. Multilevel Ternary Operator

Till now, we have used the ternary operator with one condition only. Let’s see how to use it for multiple conditions. Suppose we have to check for two conditions, one is for even, and the other is for the multiple of four. Try to write the code for the condition using the ternary operator.

n = int(input("number: "))

print("Satisfied") if n % 4 == 0 else print("Destroyed1") if n % 2 == 0 else print("Destroyed2")

Output

number: 3
Destroyed2

number: 6
Destroyed1

number: 8
Satisfied

Python executes the rightmost conditional operator first. So, in the above program, it checks whether the number is even or not first. If it’s Even then, it goes to check whether it is a multiple of four or not.

3. Python Tuple

We can use Tuple as ternary operator, it works like this:

(get_this_if_false, get_this_if_true)[condition]

Examples:

n = 20
canVote = (False, True)[n >= 18]
print(canVote)

Output

True

n = 10
canVote = (False, True)[n >= 18]
print(canVote)

Output

False

References

• Python Ternary Operators
• Python Conditional expressions