Regular Expressions 101

1st Alternative\d{3}(?<=\b\d{10}\b)

\d{3}a Unicode decimal digit, repeated exactly 3 times

Positive Lookbehind(?<=\b\d{10}\b)

\ba Unicode word boundary

\d{10}a Unicode decimal digit, repeated exactly 10 times

\ba Unicode word boundary

2nd Alternative(?=\b\d{15}\b)\d{3}

Positive Lookahead(?=\b\d{15}\b)

\ba Unicode word boundary

\d{15}a Unicode decimal digit, repeated exactly 15 times

\ba Unicode word boundary

\d{3}a Unicode decimal digit, repeated exactly 3 times

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

\d{3}(?<=\b\d{10}\b)|(?=\b\d{15}\b)\d{3}

New

8788467490
2093247823403
1284092048
739432387779983
91019283839
830082763683651
982188727212