如何使用正则表达式匹配多行

Given a unicode object with the following text:

给定具有以下文本的unicode对象：

a
b
c
d
e

aaaa
bbbb
cccc
dddd
eeee

I'd like to get the second group of lines, in other words, every line after the blank one. This is the code I've used:

我想得到第二组线，换句话说，在空白线之后的每一行。这是我用过的代码：

text = ... # the previous text
exp = u'a\nb\nc\nd\n\e\n{2}(.*\n){5}'
matches = re.findall(exp, text, re.U)

This will only retrieve the last line, indeed. What could I do to get the last five ones?

实际上，这只会检索最后一行。我能做些什么来获得最后五个？

3 个解决方案

#1

You're repeating the capturing group itself, which overwrites each match with the next repetition.

您正在重复捕获组本身，它会在下一次重复时覆盖每个匹配项。

If you do this

如果你这样做

exp = ur'a\nb\nc\nd\n\e\n{2}((?:.*\n){5})'

you get the five lines together.

你得到了五条线。

You can't get to the individual matches unless you spell out the groups manually:

除非您手动拼出组，否则无法进入单独的比赛：

exp = ur'a\nb\nc\nd\n\e\n{2}(.*\n)(.*\n)(.*\n)(.*\n)(.*\n)'

#2

Why not just:

为什么不呢：

text[text.index('\n\n') + 2:].splitlines()
# ['aaaa', 'bbbb', 'cccc', 'dddd', 'eeee']

#3

if your searched text has some kind of limitation on the number of characters for this first part which you don't want, why not set a search for only words with more than X letters like:

如果您搜索到的文本对您不想要的第一部分的字符数有某种限制，为什么不设置只搜索超过X个字母的字词，如：

^[a-z]{2,}

This will get every word bigger than 2 characters.

这将使每个单词大于2个字符。

You can control as:

你可以控制为：

{3} Exactly 3 occurrences;
{3}恰好3次出现;
{6,} At least 6 occurrences;
{6，}至少发生6次;
{2,5} 2 to 5 occurrences.
{2,5}发生2到5次。

#1