Regex match empty lines

Question

Currently I have a regex that will take a given set of newlines and condense them. A challenge I need to solve for is to modify this regex (\\n{2,}) so that it

Answer 1

Brief

This answer ensures whitespace at the start of a line is kept (if it contains something other than a whitespace character).

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Code

See regex in use here

(?:\h*\n){2,}

Note: Some regex engines don't allow \h, so this will have to be replaced with [\t\p{Zs}], and if Unicode character classes are not supported, a simple list of each character such as [\t ] or [^\S\n].

Other methods:

(?:\n(?:[^\S\n]*(?=\n))?){2,}
(?:\n(?:\s*(?=\n))?){2,}
\h*\n(?:\h*\n)+

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Results

Input

**Language**

 - Added four languages: Italian, Portuguese (Brazil), Spanish (Mexico) and Chinese (Traditional)





**Bug fixes**


 - Fixed camera jittering for passenger sitting on the back of a motorcycle with sidecar
 - Fixed camera jittering for passenger sitting on the back of a motorcycle with sidecar

Output

**Language**

 - Added four languages: Italian, Portuguese (Brazil), Spanish (Mexico) and Chinese (Traditional)

**Bug fixes**

 - Fixed camera jittering for passenger sitting on the back of a motorcycle with sidecar
 - Fixed camera jittering for passenger sitting on the back of a motorcycle with sidecar

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Explanation

• (?:\h*\n){2,} Match any number of horizontal whitespace character followed by a line-feed, two or more times

Other methods

Just to explain at least one of the other methods (and keep my original answer)

• (?:\n(?:[^\S\n]*(?=\n))?){2,} Matches the following two or more times
  • \n Match a line-feed character
  • (?:[^\S\n]*(?=\n))? Match the following zero or one time
    • [^\S\n]* Match any whitespace character except \n any number of times
    • (?=\n) Positive lookahead ensuring what follows is a line-feed \n

Answer 2

This method is shorter than the top answer:

(\h*\n){2,}

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