Python正则表达式不匹配 [英] Python regular expression not matching

问题描述

这是其中之一，我确定我遗漏了一些简单的东西，但是......在下面的示例程序中，我正在尝试使用 Python 的 RE 库来解析字符串line"以获取百分号前的浮点数，即90.31".但是代码总是打印不匹配".

This is one of those things where I'm sure I'm missing something simple, but... In the sample program below, I'm trying to use Python's RE library to parse the string "line" to get the floating-point number just before the percent sign, i.e. "90.31". But the code always prints "no match".

我也尝试了其他几个正则表达式，结果都一样.我错过了什么?

I've tried a couple other regular expressions as well, all with the same result. What am I missing?

#!/usr/bin/python
import re
line = '    0 repaired, 90.31% done'
pct_re = re.compile(' (\d+\.\d+)% done$')
#pct_re = re.compile(', (.+)% done$')
#pct_re = re.compile(' (\d+.*)% done$')
match = pct_re.match(line)
if match: print 'got match, pct=' + match.group(1)
else: print 'no match'

推荐答案

match 只匹配开头的字符串.如果您改为执行 pct_re.search(line)，您的代码可以正常工作.

match only matches from the beginning of the string. Your code works fine if you do pct_re.search(line) instead.

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