正则表达式匹配两个相同字符串之间的所有字符串

Question

Eg I have this string -- This -- is -- one -- another -- comment -- I want the matched elements to be "This", "is", "one", "another", and "comment"

I was trying this regex --\\s+([^--]+)\\s+-- which gives me the matched elements as "This", "one" and "comment"

I have searched for other problems, they all provide solution like this ie #A# and I will get A but for #A#B# also I get A , but in this case I want both the elements A and B as both of them are between two # chars.

I am testing it for javascript regex, but I think solution should be irrespective of platform/language.

Answer 1

In general, you need to use a pattern like

STRING([\s\S]*?)(?=STRING|$)

It will match STRING , then capture into Group 1 any zero or more chars, as few as possible, up to the first occurrence of STRING *stopping right before this word** because the (?=...) is a positive lookahead that, being a zero-width assertion, does not consume matched text or end of string.

A generic variation of the pattern is

STRING((?:(?!STRING)[\s\S])*)

It uses a tempered greedy token , (?:(?!STRING)[\\s\\S])* , that matches any char, 0 or more occurrences, that does not start a STRING char sequence.

To get all the substrings in the current solution, use a lookahead like

/--\s+([\s\S]*?)(?=\s+--)/g
                ^^^^^^^^^

See the regex demo .

Note that [^--]+ matches 1 or more symbols other than a - , it does not match any text that is not equal to -- . [...] is a character class that matches a single character. To match any text of any length from one char up to the first occurrence of a pattern, you can rely on a [\\s\\S]*? construct: any 0+ chars, as few as possible (due to the lazy *? quantifier).

JS demo:

 var s = '-- This -- is -- one -- another -- comment --'; var rx = /--\\s+([\\s\\S]*?)(?=\\s+--)/g; var m, res=[]; while (m = rx.exec(s)) { res.push(m[1]); } console.log(res);

Answer 2

To read all I would use positive look ahead:

 const data = '-- This -- is -- one -- another -- comment --' const readAll = data => { const regex =/--\\s*(.*?)\\s*(?=--)/g const found = [] let temp while (temp = regex.exec(data)) { found.push(temp[1]) } return found } console.log(readAll(data))

And to remove comments just do this:

 const data = `-- This -- is -- one -- another -- comment -- this is not a comment`.replace(/--.*--/g, '') console.log(data)