Python的Bitshift 32位约束 [英] Python Bitshift 32 Bit Constraint

问题描述

可能重复：结果
  <一href=\"http://stackoverflow.com/questions/2300740/problem-in-calculating-checksum-casting-int-to-signed-int32\">Problem在计算校验和：铸造诚信，以签订INT32

这应该是一个比较简单的答案，我只是真的不知道如何寻找它...我得到了一些半相关的<一个href=\"http://stackoverflow.com/questions/210629/python-unsigned-32-bit-bitwise-arithmetic\">things,但没有一个适合我想要做的。

This should be a relatively easy answer, I just don't really know how to search for it...I got a few semi-relevant things, but nothing that fits what I'm trying to do.

>>> 1171855803 << 7
149997542784L # I want -326312576

在换言之，处理的数量为整数且不允许它要转换为长。
我会怎么做呢？

In other words, treat the number as an integer and don't allow it to convert to a long. How would I do this?

我试着在<一个解决方案href=\"http://stackoverflow.com/questions/2300740/problem-in-calculating-checksum-casting-int-to-signed-int32\">this问题：

>>> x = 0xFFFFFFFF & (1171855803 << 7)
>>> if x > 0x7FFFFFFF: print -(~(x - 1) & 0xFFFFFFFF)
else: print x

-326312576L # yay!

它的工作原理！

推荐答案

也许不是最好的答案，但这个工程...

May not be the best answer, but this works...

import numpy as np
np.int32(1171855803) << 7

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