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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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

/
/
gm

Test String

Code Generator

Language

Generated Code

$re = '/^\[[[:graph:]]*\] [[:digit:]]{4}\/[[:digit:]]{2}\/[[:digit:]]{2} [[:digit:]]{2}:[[:digit:]]{2}:[[:digit:]]{2}/m'; $str = '[ERROR] 2020/12/07 11:50:43 [TDK 7a9644kyj4t6 6d99a1d9-853c-c4dd-516c-305b6c2ae52f env QCSGERFX023 ip 10.99.98.145 app default] [thread 2603] [HFAPEL] [class VrfParam:1007] [Parameters] A major error occurred while calling the \'callCurrentSession2\' function for the \'com.hardis.reflexcs.FMMA00\' class from \'HFAPEL\': incorrect type [ERROR] 2020/12/07 11:50:43 [TDK 7a9644kyj4t6 6d99a1d9-853c-c4dd-516c-305b6c2ae52f env QCSGERFX023 ip 10.99.98.145 app default] [thread 2603] [FMMA00] [class PgmSession:636] Invalid Call \'callCurrentSession2\' function of com.hardis.reflexcs.FMMA00 java.lang.IllegalArgumentException: argument type mismatch at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.hardis.adelia.template.PgmSession.invokeMethodExtCallExtFuncWithTypeCtrl(PgmSession.java:589) at com.hardis.adelia.template.PgmSession.invokeMethodExtCallExtFuncWithTypeCtrl(PgmSession.java:402) at com.hardis.reflexcs.HFAPEL._callPgmId_6(HFAPEL.java:789) at com.hardis.reflexcs.HFAPEL.UserProcAPPEL_PGM_CLIENT(HFAPEL.java:165) at com.hardis.reflexcs.HFAPEL._traiterProcUserProcAPPEL_PGM_CLIENT(HFAPEL.java:661) at com.hardis.reflexcs.HFAPEL.initPgm(HFAPEL.java:4478) at com.hardis.reflexcs.HFAPEL.javaEntry(HFAPEL.java:4588) at com.hardis.reflexcs.HFAPEL.callCurrentSession2(HFAPEL.java:4226) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.hardis.adelia.template.PgmSession.invokeMethodExtCallExtFuncWithTypeCtrl(PgmSession.java:589) at com.hardis.adelia.template.PgmSession.invokeMethodExtCallExtFuncWithTypeCtrl(PgmSession.java:402) at com.hardis.reflexcs.HFEXEP._callPgmId_5(HFEXEP.java:484) at com.hardis.reflexcs.HFEXEP$WINDOW01.Obj_IDC_VALIDER_GainFocus(HFEXEP$WINDOW01.java:310) at com.hardis.reflexcs.HFEXEP$WINDOW01.dispatchActionNumber(HFEXEP$WINDOW01.java:358) at com.hardis.wagon.runtime.Application.dispatchEvent(Application.java:318) at com.hardis.wagon.runtime.Application.sendMessage(Application.java:557) at com.hardis.adelia.cloud.tools.FocusMgr._setFocusObject(FocusMgr.java:251) at com.hardis.adelia.cloud.tools.FocusMgr.setFocusObject(FocusMgr.java:161) '; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php