正则表达式匹配句子中的整个单词 - javascript

Question

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

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

Answer 1

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 ie ***
• (?!\\*) : 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

Answer 2

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

Answer 3

/\\bs\\*{3}(\\s|$)/g可能会起作用，具体取决于您的标准是什么。