我有一个这样的字符串：
>>> s = '1,",2, ",,4,,,\',7, \',8,,10,'
>>> s
'1,",2, ",,4,,,\',7, \',8,,10,'
我想使用不同的分隔符 (not just white spaces) 将其拆分，并且我还想尊重和保留引号（单引号或双引号）。
在分隔符 , 上拆分 s 时的预期结果：
['1', ',2, ', '', '4', '', '', ',7, ', '8', '', '10', '']
【问题讨论】：
this 的修改版本（仅处理空格）可以解决问题（引号被删除）：
>>> import re
>>> s = '1,",2, ",,4,,,\',7, \',8,,10,'
>>> tokens = [t for t in re.split(r",?\"(.*?)\",?|,?'(.*?)',?|,", s) if t is not None ]
>>> tokens
['1', ',2, ', '', '4', '', '', ',7, ', '8', '', '10', '']
如果你喜欢保留引号字符：
>>> tokens = [t for t in re.split(r",?(\".*?\"),?|,?('.*?'),?|,", s) if t is not None ]
>>> tokens
['1', '",2, "', '', '4', '', '', "',7, '", '8', '', '10', '']
如果您想使用自定义分隔符，请将正则表达式中出现的, 替换为您自己的分隔符。
解释：
| = match alternatives e.g. ( |X) = space or X
.* = anything
x? = x or nothing
() = capture the content of a matched pattern
We have 3 alternatives:
1 "text" -> ".*?" -> due to escaping rules becomes - > \".*?\"
2 'text' -> '.*?'
3 delimiter -> ,
Since we want to capture the content of the text inside the quotes, we use ():
1 \"(.*?)\" (to keep the quotes use (\".*?\")
2 '(.*?)' (to keep the quotes use ('.*?')
Finally we don't want that split function reports an empty match if a
delimiter precedes and follows quotes, so we capture that possible
delimiter too:
1 ,?\"(.*?)\",?
2 ,?'(.*?)',?
Once we use the | operator to join the 3 possibilities we get this regexp:
r",?\"(.*?)\",?|,?'(.*?)',?|,"
【讨论】：
看起来您正在重新发明 python 模块 csv。包括电池。
In [1]: import csv
In [2]: s = '1,",2, ",,4,,,\',7, \',8,,10,'
In [3]: next(csv.reader([s]))
Out[3]: ['1', ',2, ', '', '4', '', '', "'", '7', " '", '8', '', '10', '']
我认为，正则表达式通常不是好的解决方案。在意想不到的时刻，它可能会出奇地慢。在csv模块中可以调整方言，很容易处理任意数量的字符串/文件。
我未能同时将 csv 调整为 quotechar 的两个变体，但您真的需要它吗？
In [4]: next(csv.reader([s], quotechar="'"))
Out[4]: ['1', '"', '2', ' "', '', '4', '', '', ',7, ', '8', '', '10', '']
或
In [5]: s = '1,",2, ",,4,,,",7, ",8,,10,'
In [6]: next(csv.reader([s]))
Out[6]: ['1', ',2, ', '', '4', '', '', ',7, ', '8', '', '10', '']
【讨论】：