regex101: PCRE (Legacy) Substitution Workspace

Definition Group(?(DEFINE) (?<tagName> [a-z][a-z\d]*+ (?=[>\s/]) ) (?<tagAttr> (?> [^>"']++ | " [^"]*+ " | ' [^']*+ ' )*+ ) )

Group tagName(?<tagName> [a-z][a-z\d]*+ (?=[>\s/]) )

Character Class[a-z]

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

Character Class[a-z\d]*+

*+matches any number of characters from the set below:

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

\da Unicode decimal digit

Positive Lookahead(?=[>\s/])

Character Class[>\s/]

>the literal > (62₁₀ / 76₈ / 3E₁₆)

\sa Unicode whitespace character

/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group tagAttr(?<tagAttr> (?> [^>"']++ | " [^"]*+ " | ' [^']*+ ' )*+ )

Atomic Group(?> [^>"']++ | " [^"]*+ " | ' [^']*+ ' )*+

*+repeats the group contents below any number of times:

1st Alternative [^>"']++

Negated Character Class[^>"']++

++matches at least one character outside the set below:

>the literal > (62₁₀ / 76₈ / 3E₁₆)

"the literal " (34₁₀ / 42₈ / 22₁₆)

'the literal ' (39₁₀ / 47₈ / 27₁₆)

2nd Alternative " [^"]*+ "

" the literal text "

Negated Character Class[^"]*+

*+matches any number of characters outside the set below:

"the literal " (34₁₀ / 42₈ / 22₁₆)

" the literal text "

3rd Alternative ' [^']*+ '

' the literal text '

Negated Character Class[^']*+

*+matches any number of characters outside the set below:

'the literal ' (39₁₀ / 47₈ / 27₁₆)

' the literal text '

< the literal text <

Group 3(li|/ul)

1st Alternativeli

lithe literal text li (case insensitive)

2nd Alternative/ul

/ulthe literal text /ul (case insensitive)

/?+optionally matches the literal / (47₁₀ / 57₈ / 2F₁₆)

Positive Lookahead(?=[>\s/])

Character Class[>\s/]

>the literal > (62₁₀ / 76₈ / 3E₁₆)

\sa Unicode whitespace character

/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 4((?&tagAttr))

(?&tagAttr)calls group tagAttr as a subroutine

> the literal text >

Group 5((?: [^<]++ | < /?+ (?!(?:li|ul)(?=[>\s/])) (?&tagName) (?&tagAttr) > #any tag except <li> and <ul> | < (?! /?+ (?&tagName) ) #not tag )*)

Non-Capturing Group(?: [^<]++ | < /?+ (?!(?:li|ul)(?=[>\s/])) (?&tagName) (?&tagAttr) > #any tag except <li> and <ul> | < (?! /?+ (?&tagName) ) #not tag )*

*repeats the group contents below any number of times:

1st Alternative [^<]++

Negated Character Class[^<]++

++matches at least one character outside the set below:

<the literal < (60₁₀ / 74₈ / 3C₁₆)

2nd Alternative < /?+ (?!(?:li|ul)(?=[>\s/])) (?&tagName) (?&tagAttr) > #any tag except <li> and <ul>

< the literal text <

/?+optionally matches the literal / (47₁₀ / 57₈ / 2F₁₆)

Negative Lookahead(?!(?:li|ul)(?=[>\s/]))

(?&tagName)calls group tagName as a subroutine

(?&tagAttr)calls group tagAttr as a subroutine

> the literal text >

Comment:any tag except <li> and <ul>

3rd Alternative < (?! /?+ (?&tagName) ) #not tag

Positive Lookahead(?= < (?:li|/ul) (?=[>\s/]) (?&tagAttr) )

Comment:check for nested <li> and <ul>

Global pattern flags

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

s modifier: single line. Allows a dot to match line terminators

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

u modifier: unicode. Treats the pattern and subject as UTF-16

X modifier: eXtra. A \ followed by a letter with no special meaning causes an error

Search reference

Regular Expression

(?(DEFINE)
  (?<tagName>
    [a-z][a-z\d]*+ (?=[>\s/])
  )
  (?<tagAttr>
    (?>
        [^>"']++
      | "  [^"]*+  "
      | '  [^']*+  '
    )*+
  )
)

< (li|/ul) /?+ (?=[>\s/]) ((?&tagAttr)) >
((?:
    [^<]++
  | < /?+  (?!(?:li|ul)(?=[>\s/]))  (?&tagName) (?&tagAttr) >  #any tag except <li> and <ul>
  | < (?! /?+ (?&tagName) ) #not tag
)*)
(?= < (?:li|/ul) (?=[>\s/]) (?&tagAttr) )  #check for nested <li> and <ul>

Test String
New

<ul>
  <li fhgfhfg ghgfhfghhfgh= ghghg="..." a = 'ghghg'>dfdsfsd
  <ul>
    <li>111</li>
    <li/>2222
    <li>mmmmm</li>
  </ul>
  <li>dfdsfdsfsdf <b class="..."><br/>fgdfgd<i></b><!-- dfdf--><li>
  <li>
  <li>dsfsdfsdfdsf
</ul>

Substitution
Processing...

<$3$4>$5</LI>\r

Regular Expression

Test StringNew

SubstitutionProcessing...

Test String
New

Substitution
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