Python基于条件分割字符串 [英] Python split string based on conditional

问题描述

如果逗号前面是某个正则表达式，我想使用逗号分隔符分割字符串.考虑我的字符串采用以下格式的情况:(一堆可能有逗号的东西)FOO_REGEX，(其他可能有逗号的东西)FOO_REGEX，..."我想用逗号分割字符串，但前提是它们前面有 FOO_REGEX:[(一堆可能有逗号的东西)FOO_REGEX"，(其他可能有逗号的东西)FOO_REGEX"，tc.].

作为一个具体的例子，考虑拆分以下字符串:

你好！$$asdf，我是 foo，bar $$jkl，很酷"

进入这个包含三个字符串的列表:

["你好！$$asdf","我是 foo, bar $$jkl",凉爽的"]

在python中有没有简单的方法可以做到这一点?

解决方案

您可以使用 re.findall 而不是 re.split.

<预><代码>>>>进口重新>>>s = "你好！$$asdf，我是 foo，bar $$jkl，很酷">>>[j for i in re.findall(r'(.*?\$\$[^,]*),\s*|(.+)', s) for j in i if j]['你好！$$asdf', '我是 foo, bar $$jkl', 'cool']

或

使用外部regex 模块来支持可变长度的lookbehind，因为re 将不支持可变长度的后视断言.

<预><代码>>>>导入正则表达式>>>s = "你好！$$asdf，我是 foo，bar $$jkl，很酷">>>regex.split(r'(?<=\$\$[^,]*),\s*', s)['你好！$$asdf', '我是 foo, bar $$jkl', 'cool']

I want to split strings using a comma delimiter if the comma is preceded by a certain regex. Consider the case where my strings are in the format: "(bunch of stuff that might have commas) FOO_REGEX, (other stuff that might have commas) FOO_REGEX, ..." and I want to split the string on commas, but only if they're preceded by FOO_REGEX: ["(bunch of stuff that might have commas) FOO_REGEX", "(other stuff that might have commas) FOO_REGEX", tc.].

As a concrete example, consider splitting the following string:

"hi, hello! $$asdf, I am foo, bar $$jkl, cool" 

into this list of three strings:

["hi, hello! $$asdf", 
"I am foo, bar $$jkl", 
"cool"]

Is there any easy way to do this in python?

解决方案

You could use re.findall instead of re.split.

>>> import re
>>> s = "hi, hello! $$asdf, I am foo, bar $$jkl, cool"
>>> [j for i in re.findall(r'(.*?\$\$[^,]*),\s*|(.+)', s) for j in i if j]
['hi, hello! $$asdf', 'I am foo, bar $$jkl', 'cool']

OR

Use external regex module to support variable length lookbehind since re won't support variable length look-behind assertions.

>>> import regex
>>> s = "hi, hello! $$asdf, I am foo, bar $$jkl, cool"
>>> regex.split(r'(?<=\$\$[^,]*),\s*', s)
['hi, hello! $$asdf', 'I am foo, bar $$jkl', 'cool']

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