Regular Expressions 101

1st Alternative.*[a-zA-Z.].*(*SKIP)(*FAIL)

.*any character (except for line terminators), repeated any number of times

Character Class[a-zA-Z.]

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

.*any character (except for line terminators), repeated any number of times

(*SKIP)acts like (*PRUNE), but the next unanchored match attempt starts where (*SKIP) was reached instead of at the next subject character

(*FAIL)forces the current match attempt to fail at this position

2nd Alternative\B(?=(\d{3})+(?!\d))

\Bnot an ASCII word boundary

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

Group 1(\d{3})+

+repeats the group contents below at least once:

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

Negative Lookahead(?!\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

Regular Expression

.*[a-zA-Z.].*(*SKIP)(*FAIL)|\B(?=(\d{3})+(?!\d))

New

Good
1
23
123
1234
12345
752892
1234567
Bad
123123456.000000
12a3123456.0000000000
123456.12345a12345

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