Regex string to find numbers not starting with 91

Question

I'm trying to narrow the following regular expression:

/\b([0-9]{22})\b/

to only match 22 digit numbers that don't start with "91". Anyone know how to do this?

Answer 1

If your regexp engine has zero width negative lookahead, then:

/\b((?!91)[0-9]{22})\b/

(?!91) causes the pattern to match only if the next two characters are not 91, but does not consume those characters, leaving them to be matched by [0-9]{22}.

Many regexp engines also allow \d for decimal digits. If yours does, then:

/\b((?!91)\d{22})\b/

Answer 2

Try this:

/\b(?:[0-8][0-9]|9[02-9])[0-9]{20}\b/