在不区分大小写的搜索期间提取与模式中使用的原始大小写的匹配 [英] Extracting matches with the original case used in the pattern during a case insensitive search

问题描述

在进行正则表达式模式匹配时，我们得到匹配的内容.如果我想要在内容中找到的模式怎么办?

请看下面的例子:

<预><代码>>>>进口重新>>>r = re.compile('ERP|Gap', re.I)>>>string = 'ERP 是 GAP 的组成部分，所以 erp 永远不能被忽略，ErP！'>>>r.findall(字符串)['ERP', 'GAP', 'erp', 'ErP']

但我希望输出看起来像这样:['ERP', 'Gap', 'ERP', 'ERP']

因为如果我对原始输出进行分组和求和，我会得到以下输出作为数据帧:

ERP 1企业资源规划 1企业资源计划 1差距1差距 1

但是如果我希望输出看起来像这样

ERP 3差距 2

与我要搜索的关键字一样吗?

更多背景

我有一个这样的关键字列表:['ERP', 'Gap'].我有一个这样的字符串:"ERP, erp, ErP, GAP, gap"

我想计算每个关键字在字符串中出现的次数.现在，如果我进行模式匹配，我会得到以下输出:[ERP, erp, ErP, GAP, gap].

现在，如果我想聚合并进行计数，我会得到以下数据框:

ERP 1企业资源规划 1企业资源计划 1差距1差距 1

虽然我希望输出看起来像这样:

ERP 3差距 2

解决方案

您可以动态构建模式以在组名称中包含您搜索的词的索引，然后抓取那些匹配的模式部分:

导入重新词 = [ERP"，差距"]words_dict = { f'g{i}':item for i,item in enumerate(words) }rx = rf"\b(?:{'|'.join([ rf'(?P<g{i}>{item})' for i,item in enumerate(words) ])})\b"text = 'ERP 是 GAP 的组成部分，所以 erp 永远不能被忽略，ErP！'结果 = []对于 re.finditer(rx, text, flags=re.IGNORECASE) 中的匹配:results.append( [words_dict.get(key) for key,value in match.groupdict().items() if value][0] )打印(结果)# =>['ERP', '差距', 'ERP', 'ERP']

查看 Python 在线演示

模式看起来像 \b(?:(?PERP)|(?PGap))\b:

• \b - 一个词边界
• (?: - 非捕获组封装模式部分的开始:
  • (?PERP) - 组g0":ERP
  • | - 或
  • (?PGap) - 组g1":Gap
• ) - 组结束
• \b - 一个词边界.

查看正则表达式演示.

注意 [0] 与 [words_dict.get(key) for key,value in match.groupdict().items() if value][0] 将在所有情况下都有效，因为当有匹配时，只有一组匹配.

While doing a regex pattern match, we get the content which has been a match. What if I want the pattern which was found in the content?

See the below example:

>>> import re
>>> r = re.compile('ERP|Gap', re.I)
>>> string = 'ERP is integral part of GAP, so erp can never be ignored, ErP!'
>>> r.findall(string)
['ERP', 'GAP', 'erp', 'ErP']

but I want the output to look like this : ['ERP', 'Gap', 'ERP', 'ERP']

Because if I do a group by and sum on the original output, I would get the following output as a dataframe:

ERP 1
erp 1
ErP 1
GAP 1
gap 1

But what if I want the output to look like

ERP 3
Gap 2

in par with the keywords I am searching for?

MORE CONTEXT

I have a keyword list like this: ['ERP', 'Gap']. I have a string like this: "ERP, erp, ErP, GAP, gap"

I want to take count of number of times each keyword has appeared in the string. Now if I am doing a pattern matching, I am getting the following output: [ERP, erp, ErP, GAP, gap].

Now if I want to aggregate and take a count, I am getting the following dataframe:

ERP 1
erp 1
ErP 1
GAP 1
gap 1

While I want the output to look like this:

ERP 3
Gap 2

解决方案

You may build the pattern dynamically to include indices of the words you search for in the group names and then grab those pattern parts that matched:

import re

words = ["ERP", "Gap"]
words_dict = { f'g{i}':item for i,item in enumerate(words) } 

rx = rf"\b(?:{'|'.join([ rf'(?P<g{i}>{item})' for i,item in enumerate(words) ])})\b"

text = 'ERP is integral part of GAP, so erp can never be ignored, ErP!'

results = []
for match in re.finditer(rx, text, flags=re.IGNORECASE):
    results.append( [words_dict.get(key) for key,value in match.groupdict().items() if value][0] )

print(results) # => ['ERP', 'Gap', 'ERP', 'ERP']

See the Python demo online

The pattern will look like \b(?:(?P<g0>ERP)|(?P<g1>Gap))\b:

• \b - a word boundary
• (?: - start of a non-capturing group encapsulating pattern parts:
  • (?P<g0>ERP) - Group "g0": ERP
  • | - or
  • (?P<g1>Gap) - Group "g1": Gap
• ) - end of the group
• \b - a word boundary.

See the regex demo.

Note [0] with [words_dict.get(key) for key,value in match.groupdict().items() if value][0] will work in all cases since when there is a match, only one group matched.

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