How to Write Inline If Statement in Python

You can write an inline if statement (ternary conditional operator) using <value_true> if <condition> else <value_false> expression in Python. Here, it returns the value_true when if condition is satisfied, otherwise the value_false will be returned.

It is a concise way to write a conditional statement. You can write nested inline if statements, but make sure they won’t be as readable because they will get complicated as you go deeper.

Traditional if-else

if condition:
    output = value_true
else:
    output = value_false

Inline if statement (ternary operator)

output = value_true if condition else value_false

Example: Simple assignment based on condition

is_holiday = True

activity = "Sleeping" if is_holiday else "Working"

print(activity)

# Output: "Sleeping"

Using an inline if in a function’s return value

Since it is a one-liner, you can use it with the return statement of a function. For example, the function accepts a value, and if it satisfies the “if condition”, its value is returned; otherwise, the “else” value is returned.

def get_discount(age):
    return "Minor" if age < 18 else "Major"


print(get_discount(15))

# Output: Minor

Since the age is 15, it is less than 18, and that means it is a Minor.

Nested Inline if Statements

You can write a nested if-else statement inline using this syntax: <value1> if <condition1> else <value2> if <condition2> else <value3>.

score = 85

grade = "A" if score >= 90 else "B" if score >= 80 else "C"

print(grade)

# Output: B

You should limit nesting to 2 levels max for readability. Always prefer parentheses for clarity when nesting. If possible, always use a regular if…elif…else for more than two conditions.

Using the ternary operator with List Comprehension

If you are creating a list out of another list where you need transformation based on conditions, you can use the inline if-else in the list comprehension.

nums = [11, 21, 18, 19, 50]

labels = ["Even" if n % 2 == 0 else "Odd" for n in nums]

print(labels)

# Output: ['Odd', 'Odd', 'Even', 'Odd', 'Even']

Inline if with Lambda Functions

If the condition is short and not complex, you can use the inline if-else with a lambda function, which itself is a shorter version of a regular function.

check_even = lambda x: "Even" if x % 2 == 0 else "Odd"

print(check_even(19))
# Output: Odd

print(check_even(50))
# Output: Even

With conditional expressions in a loop

Inside the for loop, you can use the inline if statement, and it works great, making your code smaller and readable, if not too complicated.

for i in range(5):
    print("Even" if i % 2 == 0 else "Odd")

# Output:
# Even
# Odd
# Even
# Odd
# Even

That’s all!