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

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 = "(?i)^\\s*(.*((p|post)[-.\\s]*(o|off|office)[-.\\s]*(b|box|bin)[-.\\s]*)|.*((p|post)[-.\\s]*(o|off|office)[-.\\s]*)|.*((p|post)[-.\\s]*(b|box|bin)[-.\\s]*)|(box|bin)[-.\\s]*)(#|n|num|number)?\\s*\\d+"; final String string = "-- Match\n" + "post office box 1\n" + "post office bin 1\n" + "post office b 1\n" + "post off box 1\n" + "post off bin 1\n" + "post off b 1\n" + "post o box 1\n" + "post o bin 1\n" + "post o b 1\n" + "p office box 1\n" + "p office bin 1\n" + "p office b 1\n" + "p off box 1\n" + "p off bin 1\n" + "p off b 1\n" + "p o box 1\n" + "p o bin 1\n" + "p o b 1\n" + "p-o-b-1\n" + "p.o.b.1\n" + "POB1\n" + "pob1\n" + "pob#1\n" + "pob #1\n" + "pob # 1\n" + " p o b # 1 x\n" + " p o b # 1 x\n" + "pob n1\n" + "pob num1\n" + "pob number1\n" + "foo pob1\n" + "1 pob1\n" + "box 1\n" + "bin 1\n" + "box-1\n" + "box.1\n" + "box1\n" + "BOX1\n" + "box#1\n" + "box #1\n" + "box # 1\n" + " box # 1 x\n" + " box # 1 x\n" + "po 1\n" + "po n1\n" + "PO 1\n" + "pb 1\n" + "pb n1\n" + "PB 1\n\n" + "-- No Match\n" + "foo box 1\n" + "b1\n" + "#1\n" + "1 box 1\n" + "1 pob\n" + "post 1\n" + "n1\n" + "number1\n" + "num1\n" + "post office box\n" + "post office bin\n" + "post office b\n" + "post off box\n" + "post off bin\n" + "post off b\n" + "post o box\n" + "post o bin\n" + "post o b\n" + "p office box\n" + "p office bin\n" + "p office b\n" + "p off box\n" + "p off bin\n" + "p off b\n" + "p o box\n" + "p o bin\n" + "p o b\n" + "p-o-b-\n" + "p.o.b.\n" + "POB\n" + "pob\n" + "pob#\n" + "pob #\n" + "pob #\n" + " p o b # x\n" + " p o b # x\n" + "pob n\n" + "pob num\n" + "pob number\n" + "foo pob\n" + "box\n" + "bin \n" + "box-\n" + "box.\n" + "box\n" + "BOX\n" + "box#\n" + "box #\n" + "box # \n" + " box # x\n" + " box # x\n" + "po\n" + "po n\n" + "PO\n" + "pb\n" + "pb n\n" + "PB"; 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