Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

import Foundation let pattern = #""" \h*<xen:if is="{\$debugMode}"> \h*<xen:if hascontent="true"> \h*<dl class="pairsInline debugInfo".*?> (\h*)<xen:contentcheck> """# let regex = try! NSRegularExpression(pattern: pattern) let testString = ##""" <xen:edithint template="footer.css" /> <xen:hook name="footer"> <div class="footer"> <div class="pageWidth"> <div class="pageContent"> <xen:if is="{$canChangeStyle} OR {$canChangeLanguage}"> <dl class="choosers"> <xen:if is="{$canChangeStyle}"> <dt>{xen:phrase style}</dt> <dd><a href="{xen:link 'misc/style', '', 'redirect={$requestPaths.requestUri}'}" class="OverlayTrigger Tooltip" title="{xen:phrase style_chooser}" rel="nofollow">{$visitorStyle.title}</a></dd> </xen:if> <xen:if is="{$canChangeLanguage}"> <dt>{xen:phrase language}</dt> <dd><a href="{xen:link 'misc/language', '', 'redirect={$requestPaths.requestUri}'}" class="OverlayTrigger Tooltip" title="{xen:phrase language_chooser}" rel="nofollow">{$visitorLanguage.title}</a></dd> </xen:if> </dl> </xen:if> <ul class="footerLinks"> <xen:hook name="footer_links"> <xen:if is="{$xenOptions.contactUrl.type} === 'default'"> <li><a href="{xen:link 'misc/contact'}" class="OverlayTrigger" data-overlayOptions="{&quot;fixed&quot;:false}">{xen:phrase contact_us}</a></li> <xen:elseif is="{$xenOptions.contactUrl.type} === 'custom'" /> <li><a href="{$xenOptions.contactUrl.custom}" {xen:if {$xenOptions.contactUrl.overlay}, 'class="OverlayTrigger" data-overlayOptions="{&quot;fixed&quot;:false}"'}>{xen:phrase contact_us}</a></li> </xen:if> <li><a href="{xen:link help}">{xen:phrase help}</a></li> <xen:if is="{$homeLink}"><li><a href="{$homeLink}" class="homeLink">{xen:phrase home}</a></li></xen:if> <li><a href="{$requestPaths.requestUri}#navigation" class="topLink">{xen:phrase go_to_top}</a></li> <li><a href="{xen:link forums/-/index.rss}" rel="alternate" class="globalFeed" target="_blank" title="{xen:phrase rss_feed_for_x, 'title={$xenOptions.boardTitle}'}">{xen:phrase rss}</a></li> </xen:hook> </ul> <span class="helper"></span> </div> </div> </div> <div class="footerLegal"> <div class="pageWidth"> <div class="pageContent"> <ul id="legal"> <xen:hook name="footer_links_legal"> <xen:if is="{$tosUrl}"><li><a href="{$tosUrl}">{xen:phrase terms_and_rules}</a></li></xen:if> <xen:if is="{$xenOptions.privacyPolicyUrl}"><li><a href="{$xenOptions.privacyPolicyUrl}">{xen:phrase privacy_policy}</a></li></xen:if> </xen:hook> </ul> <div id="copyright">{xen:helper copyright} {xen:phrase extra_copyright}</div> <xen:hook name="footer_after_copyright" /> <xen:if is="{$debugMode}"> <xen:if hascontent="true"> <dl class="pairsInline debugInfo" title="{$controllerName}-&gt;{$controllerAction}{xen:if $viewName, ' ({$viewName})'}"> <xen:contentcheck> <xen:if is="{$page_time}"><dt>{xen:phrase timing}:</dt> <dd><a href="{$debug_url}" rel="nofollow">{xen:phrase x_seconds, 'time={xen:number $page_time, 4}'}</a></dd></xen:if> <xen:if is="{$memory_usage}"><dt>{xen:phrase memory}:</dt> <dd>{xen:phrase x_mb, 'size={xen:number {xen:calc "{$memory_usage} / 1024 / 1024"}, 3}'}</dd></xen:if> <xen:if is="{$db_queries}"><dt>{xen:phrase db_queries}:</dt> <dd>{xen:number {$db_queries}}</dd></xen:if> </xen:contentcheck> </dl> </xen:if> </xen:if> <span class="helper"></span> </div> </div> </div> </xen:hook> """## let stringRange = NSRange(location: 0, length: testString.utf16.count) let substitutionString = #"$0\n$1 <!-- Adding XenForo version strings -->\n$1 <dt>XenForo Version:<dt> <dd>{$xenOptions.currentVersion} ({$xenOptions.currentVersionId})</dd>\n\n"# let lookupRange = (testString as NSString).range(of: pattern, options: .regularExpression, range: stringRange) if lookupRange.intersection(stringRange) != nil { let result = regex.stringByReplacingMatches(in: testString, range: lookupRange, withTemplate: substitutionString) print(result) } else { print("No matches were found.") }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Swift 5.2, please visit: https://developer.apple.com/documentation/foundation/nsregularexpression