Find indices of substrings within overlapping brackets

Question

I want to extract and locate the words within all brackets/braces in a sentence, but I am currently having trouble with overlapping brackets. e.g.:

[in]: sentence = '{ia} ({fascia} antebrachii). Genom att aponeurosen fäster i armb'
[in]: pattern = r"\[([^\[\]()]+?)\]|\(([^\[\]()]+?)\)|\{([^\[\]()]+?)\}"
[in]: [(m.start(0), m.end(0), sentence[m.start(0) : m.end(0)]) for m in re.finditer(pattern, sentence)]
[out]: [(0, 4, '{ia}'), (5, 27, '({fascia} antebrachii)')]

It should identify 3 instances and correct indices. Any advice pls?

Note you can just use `m.group(0)` in place of `sentence[m.start(0) : m.end(0)]` — Nick, Apr 13 '22 at 02:34

score 1 · Accepted Answer · answered Apr 13 '22 at 02:08

Try using the regex module. It can deal with overlapped strings:

import regex as re

sentence = '{ia} ({fascia} antebrachii). Genom att aponeurosen fäster i armb'
pattern = '{[^{}]+}|\[[^\[\]]+\]|\([^\(\)]+\)'

[(m.start(0), m.end(0), sentence[m.start(0) : m.end(0)]) for m in re.finditer(pattern, sentence, overlapped=True)]

There's also a simplified regex pattern, that matches...

everything that is not a brace among braces: {[^{}]+},
everything that is not a bracket among brackets: \[[^\[\]]+\]
everything that is not a parenthesis among parentheses: \([^\(\)]+\)

Find indices of substrings within overlapping brackets

1 Answers1