Regular Expressions 101

^start of line

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

\d*a Unicode decimal digit, repeated any number of times

Non-Capturing Group(?:[-\s]?[a-zA-Z0-9]+)?

?repeats the group contents below at most once:

Character Class[-\s]?

?matches at most one character from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\sa Unicode whitespace character

Character Class[a-zA-Z0-9]+

+matches at least one character from the set below:

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

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

0-9one character from 0 (48₁₀) to 9 (57₁₀)

$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.

25 tokens

Regular Expression

^[1-9]\d*(?:[-\s]?[a-zA-Z0-9]+)?$

New

25
25 a
25b
25-ab
12-14
0
b
0a
00a
a a
00 a
13àâäèéêë