Regular Expressions 101

^start of line

Non-Capturing Group(?:([0]{0}?\d):)?

?repeats the group contents below at most once:

Group 1([0]{0}?\d)

Character Class[0]{0}?

{0}?matches no characters from the set below:

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

\da digit

:the literal : (58₁₀ / 72₈ / 3A₁₆)

Group 2([0-5]{1}?\d)

Character Class[0-5]{1}?

{1}?matches one character from the set below:

0-5one character from 0 (48₁₀) to 5 (53₁₀)

\da digit

$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]{0}?\d):)?([0-5]{1}?\d)$