Python中的版本号比较 [英] Version number comparison in Python

问题描述

我想编写一个类似 cmp 的函数，它比较两个版本号并返回 -1、0 或 1 基于它们的比较值.

I want to write a cmp-like function which compares two version numbers and returns -1, 0, or 1 based on their compared valuses.

• 如果版本 A 比版本 B 旧，则返回 -1
• 如果版本 A 和 B 等效，则返回 0
• 如果版本 A 比版本 B 新，则返回 1

每个小节都应该被解释为一个数字，因此 1.10 > 1.1.

Each subsection is supposed to be interpreted as a number, therefore 1.10 > 1.1.

所需的函数输出是

mycmp('1.0', '1') == 0
mycmp('1.0.0', '1') == 0
mycmp('1', '1.0.0.1') == -1
mycmp('12.10', '11.0.0.0.0') == 1
...

这是我的实现，有待改进:

And here is my implementation, open for improvement:

def mycmp(version1, version2):
    parts1 = [int(x) for x in version1.split('.')]
    parts2 = [int(x) for x in version2.split('.')]

    # fill up the shorter version with zeros ...
    lendiff = len(parts1) - len(parts2)
    if lendiff > 0:
        parts2.extend([0] * lendiff)
    elif lendiff < 0:
        parts1.extend([0] * (-lendiff))

    for i, p in enumerate(parts1):
        ret = cmp(p, parts2[i])
        if ret: return ret
    return 0

顺便说一句，我使用的是 Python 2.4.5.(安装在我的工作地点......).

I'm using Python 2.4.5 btw. (installed at my working place ...).

这是一个您可以使用的小型测试套件"

Here's a small 'test suite' you can use

assert mycmp('1', '2') == -1
assert mycmp('2', '1') == 1
assert mycmp('1', '1') == 0
assert mycmp('1.0', '1') == 0
assert mycmp('1', '1.000') == 0
assert mycmp('12.01', '12.1') == 0
assert mycmp('13.0.1', '13.00.02') == -1
assert mycmp('1.1.1.1', '1.1.1.1') == 0
assert mycmp('1.1.1.2', '1.1.1.1') == 1
assert mycmp('1.1.3', '1.1.3.000') == 0
assert mycmp('3.1.1.0', '3.1.2.10') == -1
assert mycmp('1.1', '1.10') == -1

推荐答案

删除字符串中不感兴趣的部分(尾随零和点)，然后比较数字列表.

Remove the uninteresting part of the string (trailing zeroes and dots), and then compare the lists of numbers.

import re

def mycmp(version1, version2):
    def normalize(v):
        return [int(x) for x in re.sub(r'(\.0+)*$','', v).split(".")]
    return cmp(normalize(version1), normalize(version2))

这与 Pär Wieslander 的方法相同，但更紧凑:

This is the same approach as Pär Wieslander, but a bit more compact:

这里有一些测试，感谢如何在 Bash 中比较点分隔版本格式的两个字符串?":

Here are some tests, thanks to "How to compare two strings in dot separated version format in Bash?":

assert mycmp("1", "1") == 0
assert mycmp("2.1", "2.2") < 0
assert mycmp("3.0.4.10", "3.0.4.2") > 0
assert mycmp("4.08", "4.08.01") < 0
assert mycmp("3.2.1.9.8144", "3.2") > 0
assert mycmp("3.2", "3.2.1.9.8144") < 0
assert mycmp("1.2", "2.1") < 0
assert mycmp("2.1", "1.2") > 0
assert mycmp("5.6.7", "5.6.7") == 0
assert mycmp("1.01.1", "1.1.1") == 0
assert mycmp("1.1.1", "1.01.1") == 0
assert mycmp("1", "1.0") == 0
assert mycmp("1.0", "1") == 0
assert mycmp("1.0", "1.0.1") < 0
assert mycmp("1.0.1", "1.0") > 0
assert mycmp("1.0.2.0", "1.0.2") == 0

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