Unexpected Results in Integer Division: Why is 8/-7 = -2?

Integer Division Surprises

When working with integers, you might encounter an unexpected result when performing division. For instance, 8/-7 equals -2 when both numbers are treated as integers. This can be confusing, so let's explore what's happening.

Explanation

Integer division in Python 2, the version you seem to be using, follows a convention known as "floor division." This means that the result is rounded down to the nearest integer. In this case, -1.143 (the actual result of 8.0/(-7.0)) is rounded down to -2.

This behavior leads to interesting outcomes:

• 8/(-7) = -2: Rounds down to the more negative value
• 8/7 = 1: Rounds down to the closest smaller integer

Python 3 and Beyond

In Python 3, integer division has changed. Instead of rounding down, it provides a floating-point result. For example, 8/(-7) in Python 3 would be -1.143.

If you still need integer division, Python 3 offers the "//" operator. This behaves similarly to integer division in Python 2, rounding down to the nearest integer.

"Fixing" the Surprise

The apparent surprise in the integer division result can be "fixed" by upgrading to Python 3. This will result in a floating-point result, which is more representative of the true mathematical operation. Alternatively, you can use the "//" operator in Python 3 to achieve the same behavior as integer division in Python 2.

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