In Python, what is the difference between '/' and '//' when used for division?

Question

Is there a benefit to using one over the other? They both seem to return the same results.

>>> 6/3
2
>>> 6//3
2

Answer 1

// is floor division, it will always give you the integer floor of the result. The other is 'regular' division.

Answer 2

The double '//' is floor division:

>>> 7//3
2

Answer 3

// implements "floor division", regardless of your type. So 1.0/2.0 will give 0.5, but both 1/2, 1//2 and 1.0//2.0 will give 0

See http://www.python.org/doc/2.2.3/whatsnew/node7.html for details

Answer 4

6//2.5 2.0 6/2.5 2.3999999999999999

Answer 5

In Python 3.0, 5 / 2 will return 2.5 and 5 // 2 will return 2. The former is floating point division, and the latter is floor division, sometimes also called integer division.

In Python 2.2 or later in the 2.x line, there is no difference for integers unless you perform a from __future__ import division, which causes Python 2.x to adopt the behavior of 3.0

Regardless of the future import, 5.0 // 2 will return 2.0 since that's the floor division result of the operation.

You can find a detailed description at http://www.python.org/doc/2.2.3/whatsnew/node7.html

Answer 6

I think // means floor division. Could be wrong.

Answer 7

Please refer The Problem with Integer Division for the reason for introducing the // operator to do integer division.

Answer 8

As everyone has already answered, // is floor division.

Why this is important is that // is unambiguously floor division, in all Python versions from 2.2, including Python 3.x versions.

The behavior of / can change depending on:

• Active __future__ import or not (module-local)
• Python command line option, either -Q old or -Q new