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

`
`
img

Test String

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 = "\"pack_id\": \"(.*)\""; final String string = "I/okhttp.OkHttpClient: {\n" + " \"route_state\": \"give_packs\",\n" + " \"shelves\": [\n" + " {\n" + " \"pack_id\": \"100142009300S2T1599432189\",\n" + " \"shelf\": \"13\",\n" + " \"total_goods\": 2,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143022336S5T1599502063\",\n" + " \"shelf\": \"21\",\n" + " \"total_goods\": 5,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143367911S2T1599558724\",\n" + " \"shelf\": \"6\",\n" + " \"total_goods\": 2,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143699532S5T1599568344\",\n" + " \"shelf\": \"30\",\n" + " \"total_goods\": 5,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"50127475503S1T1599567324\",\n" + " \"shelf\": \"10\",\n" + " \"total_goods\": 1,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143773834S4T1599570622\",\n" + " \"shelf\": \"36\",\n" + " \"total_goods\": 4,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143789121S1T1599571959\",\n" + " \"shelf\": \"4\",\n" + " \"total_goods\": 1,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143772313S1T1599587841\",\n" + " \"shelf\": \"29\",\n" + " \"total_goods\": 1,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"50127216356S2T1599555765\",\n" + " \"shelf\": \"16\",\n" + " \"total_goods\": 2,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143911917S9T1599578036\",\n" + " \"shelf\": \"28\",\n" + " \"total_goods\": 9,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100144040317S3T1599592353\",\n" + " \"shelf\": \"45\",\n" + " \"total_goods\": 3,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"50122511688S10T1599216787\",\n" + " \"shelf\": \"14\",\n" + " \"total_goods\": 10,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143883877S3T1599580528\",\n" + " \"shelf\": \"18\",\n" + " \"total_goods\": 3,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"50125998587S5T1599460888\",\n" + " \"shelf\": \"35\",\n" + " \"total_goods\": 5,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143065694S7T1599505793\",\n" + " \"shelf\": \"19\",\n" + " \"total_goods\": 7,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"50126023780S18T1599462088\",\n" + " \"shelf\": \"23\",\n" + " \"total_goods\": 18,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143257387S1T1599516006\",\n" + " \"shelf\": \"3\",\n" + " \"total_goods\": 1,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143204003S8T1599513922\",\n" + " \"shelf\": \"42\",\n" + " \"total_goods\": 8,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100143474921S10T1599546590\",\n" + " \"shelf\": \"33\",\n" + " \"total_goods\": 10,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"50126884830S5T1599522235\",\n" + " \"shelf\": \"22\",\n" + " \"total_goods\": 5,\n" + " \"pack_state\": \"new\"\n" + " },\n" + " {\n" + " \"pack_id\": \"100142045579S1T1599431118\",\n" + " \"shelf\": \"12\",\n" + " \"total_goods\": 1,\n" + " \"pack_state\": \"new\"\n" + " }\n" + " ]\n" + "}"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE | 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