regex101: PCRE (Legacy) Match Workspace

Explanation

Pro

Definition Group(?(DEFINE) (?<nested> \[\[ [^][]*+ (?:\[\[ \g<nested> ]] [^][]*)*+ ]]) (?<part> [^][|]*+ (?: \g<nested> [^][|]* )*+ ) )

Group nested(?<nested> \[\[ [^][]*+ (?:\[\[ \g<nested> ]] [^][]*)*+ ]])

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

Negated Character Class[^][]*+

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

]the literal ] (93₁₀ / 135₈ / 5D₁₆)

[the literal [ (91₁₀ / 133₈ / 5B₁₆)

Non-Capturing Group(?:\[\[ \g<nested> ]] [^][]*)*+

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

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

\g<nested>calls group nested as a subroutine

]] the literal text ]]

Negated Character Class[^][]*

*matches any number of characters outside the set below:

]the literal ] (93₁₀ / 135₈ / 5D₁₆)

[the literal [ (91₁₀ / 133₈ / 5B₁₆)

]]the literal text ]]

Group part(?<part> [^][|]*+ (?: \g<nested> [^][|]* )*+ )

Negated Character Class[^][|]*+

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

]the literal ] (93₁₀ / 135₈ / 5D₁₆)

[the literal [ (91₁₀ / 133₈ / 5B₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

Non-Capturing Group(?: \g<nested> [^][|]* )*+

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

\g<nested>calls group nested as a subroutine

Negated Character Class[^][|]*

*matches any number of characters outside the set below:

]the literal ] (93₁₀ / 135₈ / 5D₁₆)

[the literal [ (91₁₀ / 133₈ / 5B₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

Image: the literal text Image: (case insensitive)

Group name(?<name> [^]|]* )

Negated Character Class[^]|]*

*matches any number of characters outside the set below:

]the literal ] (93₁₀ / 135₈ / 5D₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

Non-Capturing Group(?:\| (?: (?<align>left|right|center) | (?<type>thumb) | (?<size>\d+[a-z]{0,2}) | (?<description>\g<part>)))*

*repeats the group contents below any number of times:

\|the literal | (124₁₀ / 174₈ / 7C₁₆)

Non-Capturing Group(?: (?<align>left|right|center) | (?<type>thumb) | (?<size>\d+[a-z]{0,2}) | (?<description>\g<part>))

1st Alternative (?<align>left|right|center)

Group align(?<align>left|right|center)

1st Alternativeleft

leftthe literal text left (case insensitive)

2nd Alternativeright

rightthe literal text right (case insensitive)

3rd Alternativecenter

centerthe literal text center (case insensitive)

2nd Alternative (?<type>thumb)

Group type(?<type>thumb)

thumbthe literal text thumb (case insensitive)

3rd Alternative (?<size>\d+[a-z]{0,2})

Group size(?<size>\d+[a-z]{0,2})

\d+a digit, repeated at least once

Character Class[a-z]{0,2}

{0,2}matches between 0 and 2 characters from the set below:

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

4th Alternative (?<description>\g<part>)

Group description(?<description>\g<part>)

\g<part>calls group part as a subroutine

]]the literal text ]]

Global pattern flags

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

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

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

Quick Reference

25 tokens

Regular Expression

(?(DEFINE)
     (?<nested> \[\[ [^][]*+ (?:\[\[ \g<nested> ]] [^][]*)*+ ]])
     (?<part>   [^][|]*+ (?: \g<nested> [^][|]* )*+            )
)

\[\[Image: (?<name> [^]|]* ) (?:\| (?: (?<align>left|right|center) | (?<type>thumb) | (?<size>\d+[a-z]{0,2}) | (?<description>\g<part>)))* ]]

New

<mediawiki xmlns="http://www.mediawiki.org/xml/export-0.3/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.mediawiki.org/xml/export-0.3/ http://www.mediawiki.org/xml/export-0.3.xsd" version="0.3" xml:lang="en">
  <siteinfo>
    <sitename>Wikipedia</sitename>
    <base>http://en.wikipedia.org/wiki/Main_Page</base>
    <generator>MediaWiki 1.6alpha</generator>
    <case>first-letter</case>
      <namespaces>
      <namespace key="-2">Media</namespace>
      <namespace key="-1">Special</namespace>
      <namespace key="0" />
      <namespace key="1">Talk</namespace>
      <namespace key="2">User</namespace>
      <namespace key="3">User talk</namespace>
      <namespace key="4">Wikipedia</namespace>
      <namespace key="5">Wikipedia talk</namespace>
      <namespace key="6">Image</namespace>
      <namespace key="7">Image talk</namespace>
      <namespace key="8">MediaWiki</namespace>
      <namespace key="9">MediaWiki talk</namespace>
      <namespa

Substitution

<mediawiki xmlns="http://www.mediawiki.org/xml/export-0.3/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.mediawiki.org/xml/export-0.3/ http://www.mediawiki.org/xml/export-0.3.xsd" version="0.3" xml:lang="en">
  <siteinfo>
    <sitename>Wikipedia</sitename>
    <base>http://en.wikipedia.org/wiki/Main_Page</base>
    <generator>MediaWiki 1.6alpha</generator>
    <case>first-letter</case>
      <namespaces>
      <namespace key="-2">Media</namespace>
      <namespace key="-1">Special</namespace>
      <namespace key="0" />
      <namespace key="1">Talk</namespace>
      <namespace key="2">User</namespace>
      <namespace key="3">User talk</namespace>
      <namespace key="4">Wikipedia</namespace>
      <namespace key="5">Wikipedia talk</namespace>
      <namespace key="6">Image</namespace>
      <namespace key="7">Image talk</namespace>
      <namespace key="8">MediaWiki</namespace>
      <namespace key="9">MediaWiki talk</namespace>
      <namespa