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

/
/
gm

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(?:(?=(?&V_Obj))\\{|(?!^)\\G(?&Sep_Obj)\\s*)(?:(?&V_KeyVal)(?&Sep_Obj))*?\\s*(?&Str)\\s*:\\s*\\K(?&Numb)(?(DEFINE)(?<Sep_Ary>\\s*(?:,(?!\\s*[\\}\\]])|(?=\\])))(?<Sep_Obj>\\s*(?:,(?!\\s*[\\}\\]])|(?=\\})))(?<Er_Obj>(?>\\{(?:\\s*(?&Str)(?:\\s*:(?:\\s*(?:(?&Er_Value)|(?<Er_Ary>\\[(?:\\s*(?:(?&Er_Value)|(?&Er_Ary)|(?&Er_Obj))(?:(?&Sep_Ary)|(*ACCEPT)))*(?:\\s*\\]|(*ACCEPT)))|(?&Er_Obj))(?:(?&Sep_Obj)|(*ACCEPT))|(*ACCEPT))|(*ACCEPT)))*(?:\\s*\\}|(*ACCEPT))))(?<Er_Value>(?>(?&Numb)|(?>true|false|null)|(?&Str)))(?<Str>(?>\"[^\\\\\"]*(?:\\\\[\\s\\S][^\\\\\"]*)*\"))(?<Numb>(?>[+-]?(?:\\d+(?:\\.\\d*)?|\\.\\d+)(?:[eE][+-]?\\d+)?|(?:[eE][+-]?\\d+)))(?<V_KeyVal>(?>\\s*(?&Str)\\s*:\\s*(?&V_Value)\\s*))(?<V_Value>(?>(?&Numb)|(?>true|false|null)|(?&Str)|(?&V_Obj)|(?&V_Ary)))(?<V_Ary>\\[(?>\\s*(?&V_Value)(?&Sep_Ary))*\\s*\\])(?<V_Obj>\\{(?>(?&V_KeyVal)(?&Sep_Obj))*\\s*\\}))"; final String string = "{\n" + " \"first_name\":\"sample\",\n" + " \"last_name\": \"lastname\",\n" + " \"integer\" : 100,\n" + " \"float\" : 1555.20,\n" + " \"createddate\":\"2015-06-25 09:57:28\",\n" + " \"asder\" : \n" + " [ \n" + " 200, \n" + " 100,\n" + " {\n" + " \"nother1\" : \"here\",\n" + " \"digi1\" : 900e10,\n" + " \"nother1\" : \"here\",\n" + " \"digi2\" : 3.14\n" + " },\n" + " 400,\n" + " 37\n" + " ]\n" + "}"; final String subst = "\"$0\""; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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