在Python中使用re.finditer方法提取匹配的片段如何实现?

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英文:

How to extract span in re.finditer method in python?

问题

# 在 re.finditer 的结果中,我使用了 i.span 而不是 i,但我得到了如下的结果。
[i.span() for i in result]
# 我要从 re.finditer 中提取 span,像 (0,10), (12,18), ...
# 请帮帮我!
# 我定义了一个用于获取 re.finditer 结果的函数。
# 代码如下。
import re
def convert_ftn_to_token(seq):
    va = '[a-z]{1,}'

    ftn_lst = ['sin','cos','tan','log_', 'e ?\\^'] 
    ftn_lst = [ftn + ' ?\\{? ?' + va +' ?\\}?'+ ' ?\\(?' for ftn in ftn_lst]
    ftn_lst2  = [chr(i) for i in range(65,91)] + [chr(i) for i in range(97,123)]
    ftn_lst2 = [ftn + ' ?\\( ?' + va + ' ?\\)' for ftn in ftn_lst2]


    ftn_c = re.compile(
        '|'.join(ftn_lst2) +'|'+
        '|'.join(ftn_lst)
    )

    return re.finditer(ftn_c,seq)
# 对于 results 中的每一个 i,使用 i.span()。
英文:

the results of re.finditer is as below.

[i for i in result]
=[<re.Match object; span=(0, 10), match='sin theta '>,
 <re.Match object; span=(12, 18), match='cos x '>,
 <re.Match object; span=(20, 26), match='e ^ x '>,
 <re.Match object; span=(26, 32), match='f( x )'>,
 <re.Match object; span=(37, 45), match='log_ {x}'>]

Here, I used the code i.span instead of i, but I just got something as below.

[<function Match.span(group=0, /)>,
 <function Match.span(group=0, /)>,
 <function Match.span(group=0, /)>,
 <function Match.span(group=0, /)>,
 <function Match.span(group=0, /)>]

I'm gonna extract span in re.finditer.
like (0,10), (12,18), ...

Help me please!

I defined the function for getting re.finditer
The code is as below.

import re
def convert_ftn_to_token(seq):
    va = '[a-z]{1,}'

    ftn_lst = ['sin','cos','tan','log_', 'e ?\^'] 
    ftn_lst = [ftn + ' ?\{? ?' + va +' ?\}?' for ftn in ftn_lst]
    ftn_lst2  = [chr(i) for i in range(65,91)] + [chr(i) for i in range(97,123)]
    ftn_lst2 = [ftn + ' ?\( ?' + va + ' ?\)' for ftn in ftn_lst2]


    ftn_c = re.compile(
        '|'.join(ftn_lst2) +'|'+
        '|'.join(ftn_lst)
    )

    return re.finditer(ftn_c,seq)

i.span for i in results

答案1

得分: 0

You can use start() and end() in regex's Match object, documentation about it here. They correspond to the lower and upper bound of span respectively. As for the grouping stated in the docs, that only applies if you are intending to use the grouping functionality of Match. If you intend to get the span of the entire match, you can simply do match.start() and match.end(), where match is the match object returned by the regex.

Another option is using span() of the same Match object. Note this is different from just span which will give you the memory address rather than actually call the function. Doing match.span() will give you a tuple of the start and end. Taking your first match object as an example this would return (0,10)

英文:

You can use start() and end() in regex's Match object, documentation about it here. They correspond to the lower and upper bound of span respectively. As for the grouping stated in the docs, that only applies if you are intending to use the grouping functionality of Match. If you intend to get the span of the entire match, you can simply do match.start() and match.end(), where match is the match object returned by the regex.

Another option is using span() of the same Match object. Note this is different from just span which will give you the memory address rather than actually call the function. Doing match.span() will give you a tuple of the start and end. Taking your first match object as an example this would return (0,10)

答案2

得分: 0

.span 是一个方法,不是一个属性。你需要使用 .span(),它会返回开始和结束的元组。

英文:

.span is a method, not an attribute. You want .span() which will give the start, end tuple.

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  • 本文由 发表于 2023年2月16日 16:53:01
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