CODEWITHSUNDEEP
javascriptregex
Andrew Johns
Andrew Johns

Reputation: 715

RegEx for match whole word in sentences - javascript

Trying to work out what the right RegEx would be for finding "s***" in a series of strings, e.g:

match for "find s*** in s*** foobar"
match for "s***"
don't match for "s******"
don't match for "s****** foobar"

I'm using a match because I want to count the number of instances of matches in the sentence. I was trying "s*{3}" as a starting point, and variations on $ and \b or \B but I can't quite figure it out.

I created some tests here to try it out, if that's helpful.

https://regex101.com/r/VdLyOY/2

Upvotes: 1

Views: 83

Answers (3)

Ryszard Czech
Ryszard Czech

Reputation: 18641

Use

/\bs\*{3}\B(?!\*)/g

See proof

EXPLANATION

                         EXPLANATION
--------------------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
--------------------------------------------------------------------------------
  s                        's'
--------------------------------------------------------------------------------
  \*{3}                    '*' (3 times)
--------------------------------------------------------------------------------
  \B                       the boundary between two word chars (\w)
                           or two non-word chars (\W)
--------------------------------------------------------------------------------
  (?!                      look ahead to see if there is not:
--------------------------------------------------------------------------------
    \*                       '*'
--------------------------------------------------------------------------------
  )                        end of look-ahead

Upvotes: 0

anubhava
anubhava

Reputation: 786289

You may use this regex with a negative lookahead:

/\bs\*{3}(?!\*)/g

RegEx Demo

or with a positive lookahead:

/\bs\*{3}(?=\s|$)/g

RegEx Details:

  • \bs: Match letter s after a word bounday
  • \*{3}: Match * 3 times i.e. ***
  • (?!\*): Negative lookahead to assert that we don't have a * ahead
  • (?=\s|$): Positive lookahead to assert that we have a whitespace or line end at next position

Upvotes: 2

Joe Hildebrand
Joe Hildebrand

Reputation: 10414

/\bs\*{3}(\s|$)/g might work depending on exactly what your criteria are.

Upvotes: 0

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