regex101: PCRE2 (PHP) Match Workspace

Pro

1st Alternative(?<=#00FF|#FF00)[A-Fa-f0-9]{2}

Positive Lookbehind(?<=#00FF|#FF00)

1st Alternative#00FF

#00FFthe literal text #00FF (case sensitive)

2nd Alternative#FF00

#FF00the literal text #FF00 (case sensitive)

Character Class[A-Fa-f0-9]{2}

{2}matches exactly 2 characters from the set below:

A-Fone character from A (65₁₀) to F (70₁₀) (case sensitive)

a-fone character from a (97₁₀) to f (102₁₀) (case sensitive)

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

2nd Alternative[A-Fa-f0-9]{2}(?=00FF|FF00)

Character Class[A-Fa-f0-9]{2}

{2}matches exactly 2 characters from the set below:

A-Fone character from A (65₁₀) to F (70₁₀) (case sensitive)

a-fone character from a (97₁₀) to f (102₁₀) (case sensitive)

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

Positive Lookahead(?=00FF|FF00)

1st Alternative00FF

00FFthe literal text 00FF (case sensitive)

2nd AlternativeFF00

FF00the literal text FF00 (case sensitive)

3rd Alternative(?<=#00)[A-Fa-f0-9]{2}(?=FF)

Positive Lookbehind(?<=#00)

#00the literal text #00

Character Class[A-Fa-f0-9]{2}

{2}matches exactly 2 characters from the set below:

A-Fone character from A (65₁₀) to F (70₁₀) (case sensitive)

a-fone character from a (97₁₀) to f (102₁₀) (case sensitive)

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

Positive Lookahead(?=FF)

FFthe literal text FF (case sensitive)

4th Alternative(?<=#FF)[A-Fa-f0-9]{2}(?=00)

Positive Lookbehind(?<=#FF)

#FFthe literal text #FF (case sensitive)

Character Class[A-Fa-f0-9]{2}

{2}matches exactly 2 characters from the set below:

A-Fone character from A (65₁₀) to F (70₁₀) (case sensitive)

a-fone character from a (97₁₀) to f (102₁₀) (case sensitive)

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

Positive Lookahead(?=00)

00the literal text 00

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

25 tokens

Regular Expression

(?<=#00FF|#FF00)[A-Fa-f0-9]{2}|[A-Fa-f0-9]{2}(?=00FF|FF00)|(?<=#00)[A-Fa-f0-9]{2}(?=FF)|(?<=#FF)[A-Fa-f0-9]{2}(?=00)

New

Correct cases:
#FF0012
#00FFAB
#0034FF
#CD00FF
#56FF00
#FF7800

Incorrect cases:
#0000AA
#FFFFBB
#00CC00
#FFDDFF
#EE0000
#FFFFFF

Substitution

Correct cases:
#FF0012
#00FFAB
#0034FF
#CD00FF
#56FF00
#FF7800

Incorrect cases:
#0000AA
#FFFFBB
#00CC00
#FFDDFF
#EE0000
#FFFFFF