int

Converts a value to a whole number.

Synopsis

int(value)

Description

Use int on what input returns to get a number you can do maths with.

On a float, int drops everything after the decimal point. This is called truncation: int(3.9) is 3, and int(-3.9) is -3.

Parameters

Return value

An int.

Example

age = int(input("Age: "))
print(age + 1)
print(int(3.9))
print(int(-3.9))

It prints:

Age: 14
15
3
-3

Common mistake

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

Python stops with:

Number: cat
ValueError: invalid literal for int() with base 10: 'cat'

The string must hold only a whole number. "cat" fails, and so does "3.5". To accept decimals, use float.

See also

float, input, round, math.floor

int in the Python documentation