问题
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?
回答1:
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
>>>
EDIT
As commented by user2357112, this import has to be done before any other normal import.
回答2:
In Python 3, / is float division
In Python 2, / is integer division (assuming int inputs)
In both 2 and 3, // is integer division
(To get float division in Python 2 requires either of the operands be a float, either as 20. or float(20))
回答3:
In Python 2.x, make sure to have at least one operand of your division in float. Multiple ways you may achieve this as the following examples:
20. / 15
20 / float(15)
回答4:
"/" is integer division in python 2 so it is going to round to a whole number. If you would like a decimal returned, just change the type of one of the inputs to float:
float(20)/15 #1.33333333
来源：https://stackoverflow.com/questions/21316968/division-in-python-2-7-and-3-3