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

/
/
gm

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(['\"\"])((?:\\\\1|(?:(?!\\1)).)*)(\\1)|(?<OpenMatch>(\\{))|(?<CloseMatch>(\\}))"; final String string = "if (!(new[] { \"Command\", \"Click\" }).Any(d => xmlAttribute.Name.Equals(d,\n" + "StringComparison.CurrentCultureIgnoreCase))) continue;\n" + "if (!baseChain.Name.Contains(':')) return chain;\n" + "var checkAnyInherited = baseChain.Name.Split(':').Last().Split(',', ' ').Where(d => !string.IsNullOrEmpty(d)).Select(d => d.Trim()).ToList();\n" + "private static IEnumerable<StatementReferenceMaster> GetAllMethodsForClass(string className, int projectId)\n" + " {\n" + " using (ICodeVortoService codeVortoService = new CodeVortoService())\n" + " {\n" + " object[] parametersExp =\n" + " {\n" + " new MySqlParameter(\"@delim\", MySqlDbType.VarChar) {Value = \",\"},\n" + " new MySqlParameter(\"@className\", MySqlDbType.VarChar) {Value = className},\n" + " new MySqlParameter(\"@prjId\", MySqlDbType.Int32) {Value = projectId}\n" + " };\n" + " var callExtExpandedCode = codeVortoService.StatementReferenceMasterRepository\n" + " .ExecuteStoreProcedure<StatementReferenceMaster>(\"SpGetAllMethodsForClass\", parametersExp)\n" + " .ContinueWith(t => t.Result).Result;\n" + " return callExtExpandedCode;\n" + " }\n" + " }\n" + "@\"CREATE\\s+TABLE\"\n" + "@\"\\`(.*?)\\`\\s+\\(\"\n" + "@\"^\\`(.*?)\\`(.*)\"\n" + "@\"^PRIMARY\\s+KEY\"\n" + "@\"(.*)\\((.*)\\)\"\n" + "\"\"\n" + "\"\"\n" + "\"\"\n" + "\"(\"\n" + "\"-\"\n" + "\"DbScript\"\n" + " @\"CREATE\\s+TABLE\\s+(\\[dbo\\].)?(\\[)?(\\`)?(?<TableName>[a-zA-Z0-9_$]+)(\\])?(\\`)?\"\n" + "@\"^([\\s]+)?(\\[|\\`)?(?<FieldName>[a-zA-Z0-9_$]+)(\\]|\\`)?\"\n" + "\"TableName\"\n" + " @\"C:\\inetpub\\wwwroot\\flokapture\\ExtractedProjects\\LocationServicesSource\\Pods.Integration.Services.Location.Model\\LocationServiceModel.edmx\"\n" + "@\"^<EntityContainer\\s+Name=\\\"\"([^\\\"\"]*)\\\"\"\"\n" + "@\"^<EntityType\\s+Name=\\\"\"([^\\\"\"]*)\\\"\"\"\n" + "@\"StoreEntitySet=\\\"\"([^\\\"\"]*)\\\"\"\"\n" + "@\"^<Property\\s+\"\n" + "@\"^<EntityType\\s+Name=\\\"\"([^\\\"\"]*)\\\"\"|^<Property\\s+|^</EntityType>\\s+\"\n" + "\"<edmx:Mappings>\"\n" + "\"</EntityType>\"\n" + "\"Done\"\n" + "\"SELECT * FROM EntityAttributes WHERE ProjectId = \" \n" + " \" Group by EntityName;\"\n" + " @\"(?<VariableName>[a-z_]+)\\s*=\\s*new\\s+[a-z.0-9]+?\" \n" + " \"\\\\(\\\\)|[\\\\s]*[\\\\w]+\\\\s+(?<VariableName>[a-zA-Z0-9$_]+)[\\\\s]*=[\\\\s]*\"\n" + "\".\" "; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html