Find text with regular expression and get just a part of it

Question

I need to find a text with a regex, let's say "andres", but it must NOT be between []

for example if text is:

s = 'andres [andres andres] andres [andres] andresX andres'

I should get the first, fourth, sixth and the last one, others have at least one [] so they do not match.

I tried this:

"[^\[]andres[^\]]"

a better example http://jsfiddle.net/aras7/5j3UM/8/

but it does not work.

Maybe `"([^\[]andres)|(andres[^\]])|([^\[].*andres.*[^\]])"`? It'll consider `[andres`, `andres]` or `[...andres...]`. — SonicARG, May 14 '14 at 18:23
Why would you write your own name 7 times, and then try to match it with regex, shouldn't you already know what your name is ? — adeneo, May 14 '14 at 18:25
I too am interested in how this would be applied. What purpose does this piece of code serve? — 1478963, May 14 '14 at 18:26
@Sam I need it for both but I guess the regex will be the same — Andres, May 14 '14 at 18:29
2 passes on the string would work, first filter out anything between and including [], then use a simple regex to look for your text — user3203010, May 14 '14 at 18:33

score 2 · Answer 1 · edited May 23 '17 at 10:25

2

There is a useful pattern for doing this sort of thing in regex:

exclusion_context1|exclusion_context2|...|(stuff_you_want)

Where you can specify as many exclusion contexts as you want, and at the end capture the stuff you do want inside a capturing group. I could explain further but really I'll just link you to this answer which goes into great depth about the above pattern.

So, then:

\[.*?\]|(andres)

Regular expression visualization

Debuggex Demo

Where our exclusion context lazily matches anything inside brackets, and otherwise we capture all the andres outside of that context.

Since I just noticed you wanted the positions of the matches, it might look something like this in python:

for m in re.finditer(r'\[.*?\]|(andres)', s):
    if m.group(1):
        print('{}: {}'.format(m.start(),m.group()))

0: andres
23: andres
39: andres
47: andres

edited May 23 '17 at 10:25

Community

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answered May 14 '14 at 18:50

roippi

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the group at line 39 should write "andres" instead of "andresX" – Andres May 14 '14 at 19:03
oh. well, just.. put `andres` into the regex in place of the previous capturing group. Edited. – roippi May 14 '14 at 19:04
If if add "andres" it will only return (0,23 and 47), I would also like to put text with spaces like "andres arrieche" – Andres May 14 '14 at 19:07
forget my last comment, I thought you meant to put "\bandres\b" but now your answer is right – Andres May 14 '14 at 19:13
Ah, I see what you meant then. – roippi May 14 '14 at 19:13
I create an example which it fails. I'll edit my question to add it. I'll also remove python tag because my example is javascript – Andres May 14 '14 at 19:22
It's failing because you're replacing things matched by the main expression as well as the capturing group - you **only** want to replace things matched by the capturing group. – roippi May 14 '14 at 19:27
for example here http://jsfiddle.net/aras7/5j3UM/10/ it "works" but does not change the last – Andres May 14 '14 at 19:35

score 1 · Answer 2 · answered May 14 '14 at 18:39

1

Try this: test string is:

$string = 'andres [an1dres an1dres] andres [an1dres] andresX andres' ;

$patern = '/\\[.*?\\]| /';

answered May 14 '14 at 18:39

volkinc

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I need to specify a particular string, in the example I used my name but it can be whatever – Andres May 14 '14 at 18:42

score 1 · Answer 3 · answered May 14 '14 at 20:17

1

You can use the following:

\w+(?![^\[]*\])

Regular expression visualization

Demo

answered May 14 '14 at 20:17

Ulugbek Umirov

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Ron Rosenfeld · Answer 4 · 2014-05-14T18:58:48.647

Try:

andres(?=[^[\]]+(?:\[|$))

You may or may not want to set the case insensitive option.
You may or may not need to set the ^$ match at line break option.

Explanation

look for any instance of the string which is followed by a

Series of characters that is not a closing bracket and then by
either an opening bracket or the end of the string.

Explanation from RegexBuddy:

andres not between [ ... ]

andres(?=[^[\]]+(?:\[|$))

Options: Case sensitive; ^$ match at line breaks

Match the character string “andres” literally (case sensitive) «andres»
Assert that the regex below can be matched, starting at this position (positive lookahead) «(?=[^[\]]+(?:\[|$))»
   Match any single character NOT present in the list below «[^[\]]+»
      Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
      The literal character “[” «[»
      The literal character “]” «\]»
   Match the regular expression below «(?:\[|$)»
      Match this alternative (attempting the next alternative only if this one fails) «\[»
         Match the character “[” literally «\[»
      Or match this alternative (the entire group fails if this one fails to match) «$»
         Assert position at the end of a line (at the end of the string or before a line break character) (line feed, line feed, line separator, paragraph separator) «$»

Created with RegexBuddy

Find text with regular expression and get just a part of it

4 Answers4