Regular Expressions 101

Explanation

Pro

^start of string

Group 1(http(s)??\:\/\/)?

?repeats the group contents below at most once:

httpthe literal text http (case sensitive)

Group 2(s)??

??repeats the group contents below at most once:

sthe literal s (115₁₀ / 163₈ / 73₁₆) (case sensitive)

\:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 3(www\.)?

?repeats the group contents below at most once:

wwwthe literal text www (case sensitive)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 4((youtube\.com\/watch\?v=)|(youtu.be\/))

1st Alternative(youtube\.com\/watch\?v=)

Group 5(youtube\.com\/watch\?v=)

youtubethe literal text youtube (case sensitive)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

comthe literal text com (case sensitive)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

watchthe literal text watch (case sensitive)

\?the literal ? (63₁₀ / 77₈ / 3F₁₆)

v=the literal text v= (case sensitive)

2nd Alternative(youtu.be\/)

Group 6(youtu.be\/)

yoututhe literal text youtu (case sensitive)

.any character (except for line terminators)

bethe literal text be (case sensitive)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 7([a-zA-Z0-9\-_])+

+repeats the group contents below at least once:

Character Class[a-zA-Z0-9\-_]

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

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

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

$end of string, or before its final line terminator

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

^(http(s)??\:\/\/)?(www\.)?((youtube\.com\/watch\?v=)|(youtu.be\/))([a-zA-Z0-9\-_])+$

Regular Expression

Unit Tests