Regular Expressions 101

^start of line

Character Class[0-9]{0,9}

{0,9}matches between 0 and 9 characters from the set below:

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

Group 1(-[0-9]{0,4})?

?repeats the group contents below at most once:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Character Class[0-9]{0,4}

{0,4}matches between 0 and 4 characters from the set below:

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.

Search reference

Regular Expression

^[0-9]{0,9}(-[0-9]{0,4})?$

New

NoBcAl
A
-
9-
-9
-
9-
99-
999-
9999-
99999-
999999-
9999999-
99999999-
999999999
9999999999
9999999999-
9999999999-9
999999999-
999999999-9
999999999-99
999999999-999
999999999-9999
999999999--9999
999999999-99999
999999999-999999
999999999-999999-
-9
-99
-999
-9999
-99999
9-9