Regular Expressions 101

Pro

Negative Lookahead(?!^)

^start of line

Positive Lookahead(?=(?:\d{3})+(?!\.|\d))

Non-Capturing Group(?:\d{3})+

+repeats the group contents below at least once:

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

Negative Lookahead(?!\.|\d)

1st Alternative\.

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

2nd Alternative\d

\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

Detailed match information will be displayed here automatically.

25 tokens

(?!^)(?=(?:\d{3})+(?!\.|\d))

New

123456789123456789123456789
123456789
1234567
123456781234567812345678.11

,

123456789123456789123456789
123456789
1234567
123456781234567812345678.11