基本的Python算术-除法 [英] Basic python arithmetic - division

问题描述

我有两个变量:count(这是我过滤后的对象的数量)和常数per_page.我想将count除以per_page并获得整数值，但是无论我尝试什么，我都得到0或0.0:

I have two variables : count, which is a number of my filtered objects, and constant value per_page. I want to divide count by per_page and get integer value but I no matter what I try - I'm getting 0 or 0.0 :

>>> count = friends.count()
>>> print count
1
>>> per_page = 2
>>> print per_page
2
>>> pages = math.ceil(count/per_pages)
>>> print pages
0.0
>>> pages = float(count/per_pages)
>>> print pages
0.0

我在做什么错，为什么math.ceil给出浮点数而不是int?

What am I doing wrong, and why math.ceil gives float number instead of int ?

推荐答案

当两个操作数均为整数时，Python进行整数除法，这意味着1 / 2基本上是"2变成1的次数"，当然是0时代.要执行所需的操作，请按照您的期望将一个操作数转换为浮点数:1 / float(2) == 0.5.而且，math.ceil(1 / float(2))当然会产生您期望的1.

Python does integer division when both operands are integers, meaning that 1 / 2 is basically "how many times does 2 go into 1", which is of course 0 times. To do what you want, convert one operand to a float: 1 / float(2) == 0.5, as you're expecting. And, of course, math.ceil(1 / float(2)) will yield 1, as you expect.

(我认为这种划分行为在Python 3中会发生变化.)

(I think this division behavior changes in Python 3.)

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