Python – Integer Division in Python 2 and Python 3

divisionpythonpython-2.7python-3.x

How can I divide two numbers in Python 2.7 and get the result with decimals?

I don't get it why there is difference:

in Python 3:

>>> 20/15
1.3333333333333333

in Python 2:

>>> 20/15
1

Isn't this a modulo actually?

Best Answer

In Python 2.7, the / operator is integer division if inputs are integers.

If you want float division (which is something I always prefer), just use this special import:

from __future__ import division

See it here:

>>> 7 / 2
3
>>> from __future__ import division
>>> 7 / 2
3.5
>>>

Integer division is achieved by using //, and modulo by using %:

>>> 7 % 2
1
>>> 7 // 2
3
>>>

As commented by user2357112, this import has to be done before any other normal import.

Related Solutions

Python – Differences in Division Results Between Python 2 and 3

/ is a different operator in Python 3; in Python 2 / alters behaviour when applied to 2 integer operands and returns the result of a floor-division instead:

>>> 3/2   # two integer operands
1
>>> 3/2.0 # one operand is not an integer, float division is used
1.5

Add:

from __future__ import division

to the top of your code to make / use float division in Python 2, or use // to force Python 3 to use integer division:

>>> from __future__ import division
>>> 3/2    # even when using integers, true division is used
1.5
>>> 3//2.0 # explicit floor division
1.0

Using either of these techniques works in Python 2.2 or newer. See PEP 238 for the nitty-gritty details of why this was changed.

Best Answer

Related Solutions

Python – Differences in Division Results Between Python 2 and 3

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