Regular Expressions 101

Explanation

Pro

^start of string

Group 1(https?:\/\/)?

?repeats the group contents below at most once:

httpthe literal text http (case sensitive)

s?optionally matches the literal s (115₁₀ / 163₈ / 73₁₆) (case sensitive)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 2(localhost|lvh\.me|::1?|fe80::1|((::f{4}:)?(1(0|27)\.\d{1,3}|172\.(1[6-9]|2\d|3[01])|192\.168)\.\d{1,3}\.\d{1,3}))

1st Alternativelocalhost

localhostthe literal text localhost (case sensitive)

2nd Alternativelvh\.me

lvhthe literal text lvh (case sensitive)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

methe literal text me (case sensitive)

3rd Alternative::1?

::the literal text ::

1?optionally matches the literal 1 (49₁₀ / 61₈ / 31₁₆)

4th Alternativefe80::1

fe80::1the literal text fe80::1 (case sensitive)

5th Alternative((::f{4}:)?(1(0|27)\.\d{1,3}|172\.(1[6-9]|2\d|3[01])|192\.168)\.\d{1,3}\.\d{1,3})

Group 3((::f{4}:)?(1(0|27)\.\d{1,3}|172\.(1[6-9]|2\d|3[01])|192\.168)\.\d{1,3}\.\d{1,3})

Group 4(::f{4}:)?

?repeats the group contents below at most once:

::the literal text ::

f{4}the literal f (102₁₀ / 146₈ / 66₁₆) (case sensitive), repeated exactly 4 times

:the literal : (58₁₀ / 72₈ / 3A₁₆)

Group 5(1(0|27)\.\d{1,3}|172\.(1[6-9]|2\d|3[01])|192\.168)

1st Alternative1(0|27)\.\d{1,3}

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Group 6(0|27)

1st Alternative0

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2nd Alternative27

27the literal text 27

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{1,3}a digit, repeated between 1 and 3 times

2nd Alternative172\.(1[6-9]|2\d|3[01])

172the literal text 172

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 7(1[6-9]|2\d|3[01])

1st Alternative1[6-9]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[6-9]

6-9one character from 6 (54₁₀) to 9 (57₁₀)

2nd Alternative2\d

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

\da digit

3rd Alternative3[01]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3rd Alternative192\.168

192the literal text 192

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

168the literal text 168

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{1,3}a digit, repeated between 1 and 3 times

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{1,3}a digit, repeated between 1 and 3 times

Group 8(:\d{1,5})?

?repeats the group contents below at most once:

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\d{1,5}a digit, repeated between 1 and 5 times

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

Unit Test Summary

Ready to run

Quick Reference

25 tokens

Regular Expression

^(https?:\/\/)?(localhost|lvh\.me|::1?|fe80::1|((::f{4}:)?(1(0|27)\.\d{1,3}|172\.(1[6-9]|2\d|3[01])|192\.168)\.\d{1,3}\.\d{1,3}))(:\d{1,5})?

Unit Tests