Python Ternary Conditional Operator

The Python ternary operator returns a value based on whether a condition is True or False. It is similar to an if-else statement but is expressed in a single line.

For understanding the ternary operator, we need to have an idea about conditional statements. Let's have a basic understanding of the if-else statement. We will have an if block followed by an else block here. The if block is executed when the given condition is True, and the else block is executed if the given condition is False.

The following is the basic syntax of the if-else statement -

if condition:
   statement1
   statement2
else:
   statement3
   statement4

Let's understand the if-else statement with the following example. Here, the value of var is greater than zero; this condition returns true, so the if block is executed -

var = 14
if var>0:
   print("The given condition is True")
else:
   print("The given condition is False")

Following is the output of the above code -

The given condition is True

What is a ternary operator?

The ternary operator allows us to evaluate the given condition if it is True or False. It contains two sets of statements, the first set (say true_value) is followed by the if keyword, a condition, the else keyword, and then the second set of statements (say false_value).

If the given condition is True, this operator will return true_value; else, it will return false_value. This operator is concise and can replace an if-else statement in a single line of code.

Syntax of Ternary Operator

Following is the syntax of the Python Ternary Operator -

true_value if condition else false_value

Example : Ternary Operator

Following is a basic example of the Python ternary operator -

var_1 = 10
var_2 = 45
result ="var_1 is less than var_2" if 10 < 24 else "var_2 is greater than var_1" 
print(result)

Output

Following is the output of the above code -

var_1 is less than var_2

Ternary Operator with different data types

The ternary operator can be used with different data types -

• Using tuples
• Using dictionary
• Using lambda()

Using Python Tuples

The ternary operator can be used with Python tuples. The 0 and 1 index values are specified with false_value and true_value values, respectively. If the given condition is True, it will return the value at index 1. If the given condition is False, then it will return the value at the 0 index.

Syntax

Following is the syntax of the Python ternary operator using a tuple -

(false_value, true_value)[condition]

Example

Let's understand the usage ternary operator with tuples -

var_1 = 15
var_2 = 0
result = ("var_1 and var_2 : False","var_1 and var_2 : True")[ var_1 and var_2]
print(result)

Output

Following is the output of the above code -

var_1 and var_2 : False

Using Python dictionary

The ternary operator can be used with a Python dictionary. The keys are True and False, and the values are true_value and false_value. If the condition is True, the value corresponding to the True key is returned; otherwise, the value corresponding to the False key is returned.

Syntax

Following is the syntax of the Python ternary operator using dictionary ?

{True:true_value, False:false_value}[condition]

Example

Following is an example of the Python ternary operator using dictionary ?

var_1 = 1
var_2 = 0
result = {True:"var_1 or var_2 : True",False:"var_1 or var_2 : False"}[var_1 or var_2]
print(result)

Output

Following is the output of the above code -

var_1 or var_2 : True

Using lambda

We can also use the ternary operator with lambda. This is similar to a tuple where false_value is at 0 index and true_value at 1. If the condition is True it will return the index 1 value. Otherwise, the value corresponds to the 0 index.

Syntax

Following is the syntax of the Python ternary operator using lambda -

(lambda : false_value, lambda : true_value)[condition]()

Example

In the following example we have performed the ternary Operator using lambda -

var_1 = 8
result = (lambda : "False",lambda : "True")[var_1 < 0]()
print(result)

Output

Following is the output of the above code -

False

Nested Ternary Operator

The ternary operator can be used instead of a nested if-else statement. If we use a ternary operator inside another ternary operator, it is known as a nested ternary operator.

Syntax

Following is the syntax of the Python nested ternary operator -

true_value  if condition1 else (true_value if condition2  else false_value)

Example

Following is an example of the Python nested ternary operator -

var_1 = 50
var_2 = 80

print("Both are equal" if var_1 == var_2 else "var_1 is greater"
      if var_1 > var_2 else "var_2 is greater")

Output

Following is the output of the above code -

var_2 is greater