How do you match 12 hour time hh:mm in a regex?

Question

How could you match 12 hour time in a regex-- in other words match 12:30 but not 14:74? Thanks!

Answer 1

^(00|0[0-9]|1[012]):[0-5][0-9] ?((a|p)m|(A|P)M)$

^ - Match the beginning of the string.

(00|0[0-9]|1[012]) - any two-digit number up to 12. Require two digits.

: - Match a colon

[0-5][0-9] - Match any two-digit number from 00 to 59.

? - Match a space zero or one times.

((a|p)m|(A|P)M) - Match am or pm, case insensitive.

$ - Match the end of the string.