Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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

/
/
g

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"((<svg:svg )(\w+=\""[\w\.]+\"" )+)(height=\""\d+\"")"; string substitution = @"$1height=""xxx"""; string input = @"<svg:svg version=""1.1"" baseProfile=""full"" width=""771"" height=""221"" xmlns:svg=""http://www.w3.org/2000/svg""><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.transitorio/table_dboah_causal_no_genuino.htm"" title=""table: dbo.ah_causal_no_genuino"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:rect rx=""5"" ry=""5"" x=""78"" y=""24"" width=""16"" height=""16"" style=""fill:#0000FF; stroke:#0000FF; stroke-width:1; fill-opacity:0.5"" /></svg:a><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.transitorio/table_dboah_causal_no_genuino.htm"" title=""table: dbo.ah_causal_no_genuino"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:text font-size=""10"" font-family=""verdana"" x=""46"" y=""52"">ah_causal_no_genuino</svg:text></svg:a><svg:line style=""stroke:#808080;stroke-width:1"" x1=""320"" y1=""120"" x2=""86"" y2=""32"" /><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.cob_ahorros/table_dboah_cuenta.htm"" title=""table: dbo.ah_cuenta"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:rect rx=""5"" ry=""5"" x=""312"" y=""0"" width=""16"" height=""16"" style=""fill:#0000FF; stroke:#0000FF; stroke-width:1; fill-opacity:0.5"" /></svg:a><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.cob_ahorros/table_dboah_cuenta.htm"" title=""table: dbo.ah_cuenta"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:text font-size=""10"" font-family=""verdana"" x=""296"" y=""28"">ah_cuenta</svg:text></svg:a><svg:line style=""stroke:#808080;stroke-width:1"" x1=""320"" y1=""120"" x2=""320"" y2=""8"" /><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.cob_ahorros_his/table_dboah_his_movimiento.htm"" title=""table: dbo.ah_his_movimiento"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:rect rx=""5"" ry=""5"" x=""545"" y=""24"" width=""16"" height=""16"" style=""fill:#0000FF; stroke:#0000FF; stroke-width:1; fill-opacity:0.5"" /></svg:a><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.cob_ahorros_his/table_dboah_his_movimiento.htm"" title=""table: dbo.ah_his_movimiento"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:text font-size=""10"" font-family=""verdana"" x=""517"" y=""52"">ah_his_movimiento</svg:text></svg:a><svg:line style=""stroke:#808080;stroke-width:1"" x1=""320"" y1=""120"" x2=""553"" y2=""32"" /><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.cobis/table_dbocl_catalogo.htm"" title=""table: dbo.cl_catalogo"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:rect rx=""5"" ry=""5"" x=""78"" y=""74"" width=""16"" height=""16"" style=""fill:#0000FF; stroke:#0000FF; stroke-width:1; fill-opacity:0.5"" /></svg:a><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.cobis/table_dbocl_catalogo.htm"" title=""table: dbo.cl_catalogo"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:text font-size=""10"" font-family=""verdana"" x=""59"" y=""102"">cl_catalogo</svg:text></svg:a><svg:line style=""stroke:#808080;stroke-width:1"" x1=""320"" y1=""120"" x2=""86"" y2=""82"" /><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.cobis/table_dbocl_tabla.htm"" title=""table: dbo.cl_tabla"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:rect rx=""5"" ry=""5"" x=""312"" y=""50"" width=""16"" height=""16"" style=""fill:#0000FF; stroke:#0000FF; stroke-width:1; fill-opacity:0.5"" /></svg:a><svg:a target=""basefrm"" xlink:href=""../Sybase.Central.cobis/table_dbocl_tabla.htm"" title=""table: dbo.cl_tabla"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:text font-size=""10"" font-family=""verdana"" x=""298"" y=""78"">cl_tabla</svg:text></svg:a><svg:line style=""stroke:#808080;stroke-width:1"" x1=""320"" y1=""120"" x2=""320"" y2=""58"" /><svg:a target=""basefrm"" xlink:href=""sp_dbosp_movimientos_genuinos.htm"" title=""stored procedure: dbo.sp_movimientos_genuinos"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:rect rx=""5"" ry=""5"" x=""310"" y=""110"" width=""20"" height=""20"" style=""fill:#FF0000; stroke:#FF0000; stroke-width:1; fill-opacity:0.5"" /></svg:a><svg:a target=""basefrm"" xlink:href=""sp_dbosp_movimientos_genuinos.htm"" title=""stored procedure: dbo.sp_movimientos_genuinos"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:text font-size=""10"" font-family=""verdana"" x=""275"" y=""140"">sp_movimientos_genuinos</svg:text></svg:a><svg:a target=""basefrm"" xlink:href=""../ExternalObjects/Sqr_Jubilacionesju_devolucion.htm"" title=""Sqr: Jubilaciones.ju_devolucion"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:rect rx=""5"" ry=""5"" x=""137"" y=""162"" width=""16"" height=""16"" style=""fill:#B96A9A; stroke:#B96A9A; stroke-width:1; fill-opacity:0.5"" /></svg:a><svg:a target=""basefrm"" xlink:href=""../ExternalObjects/Sqr_Jubilacionesju_devolucion.htm"" title=""Sqr: Jubilaciones.ju_devolucion"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:text font-size=""10"" font-family=""verdana"" x=""115"" y=""190"">ju_devolucion</svg:text></svg:a><svg:line style=""stroke:#808080;stroke-width:1"" x1=""320"" y1=""120"" x2=""145"" y2=""170"" /><svg:a target=""basefrm"" xlink:href=""../ExternalObjects/Sqr_Jubilacionesju_rendicion_asig_fam.htm"" title=""Sqr: Jubilaciones.ju_rendicion_asig_fam"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:rect rx=""5"" ry=""5"" x=""487"" y=""162"" width=""16"" height=""16"" style=""fill:#B96A9A; stroke:#B96A9A; stroke-width:1; fill-opacity:0.5"" /></svg:a><svg:a target=""basefrm"" xlink:href=""../ExternalObjects/Sqr_Jubilacionesju_rendicion_asig_fam.htm"" title=""Sqr: Jubilaciones.ju_rendicion_asig_fam"" xmlns:xlink=""http://www.w3.org/1999/xlink""><svg:text font-size=""10"" font-family=""verdana"" x=""453"" y=""190"">ju_rendicion_asig_fam</svg:text></svg:a><svg:line style=""stroke:#808080;stroke-width:1"" x1=""320"" y1=""120"" x2=""495"" y2=""170"" /></svg:svg>"; Regex regex = new Regex(pattern); string result = regex.Replace(input, substitution); } }

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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx