Regular Expressions 101

Pro

^start of line

Non-Capturing Group(?:(?:[01]?[0-9]|2[0-3]):[0-5][0-9](?:[ECMP]ST|UTC)|\d+(?:\.\d+)?[mh])

1st Alternative(?:[01]?[0-9]|2[0-3]):[0-5][0-9](?:[ECMP]ST|UTC)

Non-Capturing Group(?:[01]?[0-9]|2[0-3])

1st Alternative[01]?[0-9]

Character Class[01]?

?matches at most one character from the set below:

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-9]

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

2nd Alternative2[0-3]

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-3]

0-3one character from 0 (48₁₀) to 3 (51₁₀)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

Character Class[0-5]

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

Character Class[0-9]

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

Non-Capturing Group(?:[ECMP]ST|UTC)

1st Alternative[ECMP]ST

Character Class[ECMP]

Ethe literal E (69₁₀ / 105₈ / 45₁₆) (case sensitive)

Cthe literal C (67₁₀ / 103₈ / 43₁₆) (case sensitive)

Mthe literal M (77₁₀ / 115₈ / 4D₁₆) (case sensitive)

Pthe literal P (80₁₀ / 120₈ / 50₁₆) (case sensitive)

STthe literal text ST (case sensitive)

2nd AlternativeUTC

UTCthe literal text UTC (case sensitive)

2nd Alternative\d+(?:\.\d+)?[mh]

\d+a Unicode decimal digit, repeated at least once

Non-Capturing Group(?:\.\d+)?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d+a Unicode decimal digit, repeated at least once

Character Class[mh]

mthe literal m (109₁₀ / 155₈ / 6D₁₆) (case sensitive)

hthe literal h (104₁₀ / 150₈ / 68₁₆) (case sensitive)

$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

^(?:(?:[01]?[0-9]|2[0-3]):[0-5][0-9](?:[ECMP]ST|UTC)|\d+(?:\.\d+)?[mh])$

New

0:30EST
00:30PST
22:15MST
13:51UTC
12.5m
555h
---
33:47EST
1:25GMT
123:56EST
12:356EST
AB
EST
h
55.55.55h

Substitution

0:30EST
00:30PST
22:15MST
13:51UTC
12.5m
555h
---
33:47EST
1:25GMT
123:56EST
12:356EST
AB
EST
h
55.55.55h