Regular Expressions 101

^start of line

\d+a digit, repeated at least once

Group 1([\ _.,])?

?repeats the group contents below at most once:

Character Class[\ _.,]

\ the literal (32₁₀ / 40₈ / 20₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\d*a digit, repeated any number of times

Non-Capturing Group(?:\1\d+)*

*repeats the group contents below any number of times:

\1the text saved by group 1

\d+a digit, repeated at least once

$end of line

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+([\ _.,])?\d*(?:\1\d+)*$

New

1
1234
3.14159
12_456_789
123.456.789.0
123,456.789_987