Python2/3对同一个数学运算给出不同的答案…为什么？（计算百分比差异）

Question

python2和python3对于求两个量之间的百分比差的非常简单的数学操作，似乎得到了不同的答案。在

例如：

# Python 2.7.10
>>> def percent_difference(qty1, qty2):
...     diff = max(qty1, qty2) - min(qty1, qty2)
...     print(diff)
...     percent = diff / ( (qty1 + qty2) / 2)
...     print(percent)
... 
>>> percent_difference(1, 2)
1
1

# Python 3.6.2

>>> def percent_difference(qty1, qty2):
...     diff = max(qty1, qty2) - min(qty1, qty2)
...     print(diff)
...     percent = diff / ( (qty1 + qty2) / 2)
...     print(percent)
... 
>>> percent_difference(1, 2)
1
0.6666666666666666

这是怎么回事？在

（Python3是正确的）

Answer 1

您需要告诉Python您需要float输出。 尝试percent_difference(1.0, 2.0)