使用通配符 Python 查找复杂的子字符串

Question

我正在尝试在长字符串中定位表达式的位置。该表达式的工作原理如下。它由 list1 的任何元素给出，后跟 1 到 5 个单词的通配符（以空格分隔），然后是 list2 的任何元素。例如：

list1=["a","b"], list2=["c","d"]
text = "bla a tx fg hg gfgf tzt zt blaa  a  bli blubb d  muh meh  muh d"

应该返回“37”，因为这是找到表达式（“a bli blubb d”）的地方。我研究了正则表达式通配符，但我很难将它与列表的不同元素以及通配符的可变长度放在一起。

感谢任何建议！

Answer 1

你可以构造一个正则表达式：

import re

pref=["a","b"]
suff=["c","d"]

# the pattern is dynamically constructed from your pref and suff lists.
patt = r"(?:\W|^)((?:" + '|'.join(pref) + r")(?: +[^ ]+){1,5} +(?:" + '|'.join(suff) + r"))(?:\W|$)"

text = "bla a tx fg hg gfgf tzt zt blaa  a  bli blubb d  muh meh  muh d"

print(patt)

for k in re.findall(patt,text):
    print(k, "\n", text.index(k))

输出：

(?:\W|^)((?:a|b)(?: +[^ ]+){1,5} +(?:c|d))(?:\W|$)  # pattern
a  bli blubb d                                      # found text
33                                                  # position (your 37 is wrong btw.)

公平警告：这不是一个非常可靠的方法。

正则表达式类似于：

Either start of line or non-text character (not captured) followed by
one of your prefs. followed by 1-n spaces, followed by 1-5 non-space things that 
are seperated by 1-n spaces, followed by something from suff followed
by (non captured non-Word-Character or end of line)

有关组装正则表达式的演示和更完整的描述：请参阅https://regex101.com/r/WHZfr9/1