match closest value pair

Question

how would one find the closest match string to another string

so for example

string1:val1 ... string1:val2 .... string2:val3 ...

should capture the closest string1 to string2 which would be "string1:val2"

string1 can appear any number of times.
the in between characters can be anything

See [`.*"title":(.*)"value":`](https://regex101.com/r/Ctu9h8/1). — Wiktor Stribiżew, Feb 13 '17 at 19:26
@WiktorStribiżew there coud be unlimited # of first string preceding — michael, Feb 13 '17 at 19:29
@WiktorStribiżew last "title":" " which is closest to "value":" " — michael, Feb 13 '17 at 19:33
@WiktorStribiżew could have any characters after "title" including " so that wont work. think of it as a general question — michael, Feb 13 '17 at 19:35
@m.r. - what if string is `"title":"text2" asjdsjsd "value":"val1" "title":"text3"`? — Gurwinder Singh, Feb 13 '17 at 19:38
You mean *escaped* quotes? Ok, see [this demo](http://ideone.com/g5gcRy) with `'/.*"title":"([^"\\\\]*(?:\\\\.[^"\\\\]*)*)"/i'`. Or I think my first comment suggestion is quite valid - http://ideone.com/34P8Jz. — Wiktor Stribiżew, Feb 13 '17 at 19:38
@GurV so then should get closest title to "value" in your case, "title":"text2" — michael, Feb 13 '17 at 19:38
@WiktorStribiżew looking for a general answer. i'll update question to clarify — michael, Feb 13 '17 at 19:39
See [this answer](http://stackoverflow.com/a/37343088/3832970). What sln suggests is a tempered greedy token. — Wiktor Stribiżew, Feb 13 '17 at 19:52

score 2 · Accepted Answer · 2017-02-13T22:07:56.113

2

Easiest way is something like (?s)"title":(?:(?!"title":).)*?"value":".*?"

 (?s)                    # Dot-all modifier
 "title":                # Literal 'title'
 (?:                     # Group start
      (?! "title": )          # Negative assertion, not 'title' ahead
      .                       # Ok, grab this chakracter
 )*?                     # Group end, do 0 to many times
 "value":" .*? "         # Until 'value' is found

Output

  **  Grp 0 -  ( pos 73 , len 39 ) 
 "title":"text2" asjdsjsd "value":"val1"

edited Feb 13 '17 at 22:07

answered Feb 13 '17 at 19:41

what is (?s) for? can you explain what this does. thanks – michael Feb 13 '17 at 19:47
It's a regex construct called an _Inline Modifier_. The `s` means Dot-all = (the . )matches any character including newlines. – Feb 13 '17 at 19:49
and what is (?! would be helpful if you could explain the steps if possible – michael Feb 13 '17 at 19:51
Added comments. – Feb 13 '17 at 19:54

match closest value pair

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