What Does the // Operator Do?

In Python, the // operator is the floor division operator that divides two numbers and rounds the result down to the nearest integer. This is different from regular division (/) which returns a float result.

Syntax

The basic syntax for floor division is ?

a // b

Where a is the dividend and b is the divisor.

Basic Floor Division Example

Let's see how floor division works with positive numbers ?

a = 37
b = 11

print("First Number:", a)
print("Second Number:", b)

# Floor division
result = a // b
print("Floor Division Result:", result)

# Regular division for comparison
regular_result = a / b
print("Regular Division Result:", regular_result)

First Number: 37
Second Number: 11
Floor Division Result: 3
Regular Division Result: 3.3636363636363638

Floor Division with Negative Numbers

Floor division always rounds down to the nearest integer, which means it rounds toward negative infinity ?

# Negative dividend
a = -37
b = 11

print("First Number:", a)
print("Second Number:", b)

result = a // b
print("Floor Division Result:", result)

regular_result = a / b
print("Regular Division Result:", regular_result)

First Number: -37
Second Number: 11
Floor Division Result: -4
Regular Division Result: -3.3636363636363638

Notice that -37 // 11 gives -4 (not -3) because floor division rounds down toward negative infinity.

More Examples

Here are additional examples showing different scenarios ?

# Various floor division examples
examples = [
    (15, 4),
    (-15, 4),
    (15, -4),
    (-15, -4)
]

for a, b in examples:
    floor_result = a // b
    regular_result = a / b
    print(f"{a} // {b} = {floor_result} (regular: {regular_result:.2f})")

15 // 4 = 3 (regular: 3.75)
-15 // 4 = -4 (regular: -3.75)
15 // -4 = -4 (regular: -3.75)
-15 // -4 = 3 (regular: 3.75)

Comparison

Conclusion

The // operator performs floor division, always rounding down toward negative infinity. Use it when you need integer division results, especially in algorithms requiring whole number quotients.