Regular Expressions 101

Explanation

Pro

1st Alternative(?=(?:\d|(?<=\d)[_\W]\d){4,5})\d

Positive Lookahead(?=(?:\d|(?<=\d)[_\W]\d){4,5})

Non-Capturing Group(?:\d|(?<=\d)[_\W]\d){4,5}

{4,5}repeats the group contents below between 4 and 5 times:

1st Alternative\d

\da digit

2nd Alternative(?<=\d)[_\W]\d

Positive Lookbehind(?<=\d)

\da digit

Character Class[_\W]

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\Wany non-word character

\da digit

\da digit

2nd Alternative(?<=(?<!^)\G)\d

Positive Lookbehind(?<=(?<!^)\G)

Negative Lookbehind(?<!^)

^start of line

\Gstart of current search

\da digit

3rd Alternative(?<=\d)[_\W]\d

Positive Lookbehind(?<=\d)

\da digit

Character Class[_\W]

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\Wany non-word character

\da digit

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

25 tokens

Regular Expression

(?=(?:\d|(?<=\d)[_\W]\d){4,5})\d|(?<=(?<!^)\G)\d|(?<=\d)[_\W]\d

New

any text 000 00 more texts" will become "any text ***** more texts"..notice that the space is removed

"any text 000 00 more texts 00" will become "any text ***** more texts 00"

"any text 000 00 more texts 00 00" will become "any text ***** more texts ****"
"any text 00-00 more texts 00_00" will become "any text **** more texts ****"

Extraction

any text 000 00 more texts" will become "any text ***** more texts"..notice that the space is removed

"any text 000 00 more texts 00" will become "any text ***** more texts 00"

"any text 000 00 more texts 00 00" will become "any text ***** more texts ****"
"any text 00-00 more texts 00_00" will become "any text **** more texts ****"