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

/
/
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 = "^(?:[1-9]?\\d|1\\d\\d|2[0-4]\\d|25[0-5])$"; final String string = "1\n" + "2\n" + "3\n" + "4\n" + "5\n" + "6\n" + "7\n" + "8\n" + "9\n" + "10\n" + "11\n" + "12\n" + "13\n" + "14\n" + "15\n" + "16\n" + "17\n" + "18\n" + "19\n" + "20\n" + "21\n" + "22\n" + "23\n" + "24\n" + "25\n" + "26\n" + "27\n" + "28\n" + "29\n" + "30\n" + "31\n" + "32\n" + "33\n" + "34\n" + "35\n" + "36\n" + "37\n" + "38\n" + "39\n" + "40\n" + "41\n" + "42\n" + "43\n" + "44\n" + "45\n" + "46\n" + "47\n" + "48\n" + "49\n" + "50\n" + "51\n" + "52\n" + "53\n" + "54\n" + "55\n" + "56\n" + "57\n" + "58\n" + "59\n" + "60\n" + "61\n" + "62\n" + "63\n" + "64\n" + "65\n" + "66\n" + "67\n" + "68\n" + "69\n" + "70\n" + "71\n" + "72\n" + "73\n" + "74\n" + "75\n" + "76\n" + "77\n" + "78\n" + "79\n" + "80\n" + "81\n" + "82\n" + "83\n" + "84\n" + "85\n" + "86\n" + "87\n" + "88\n" + "89\n" + "90\n" + "91\n" + "92\n" + "93\n" + "94\n" + "95\n" + "96\n" + "97\n" + "98\n" + "99\n" + "100\n" + "101\n" + "102\n" + "103\n" + "104\n" + "105\n" + "106\n" + "107\n" + "108\n" + "109\n" + "110\n" + "111\n" + "112\n" + "113\n" + "114\n" + "115\n" + "116\n" + "117\n" + "118\n" + "119\n" + "120\n" + "121\n" + "122\n" + "123\n" + "124\n" + "125\n" + "126\n" + "127\n" + "128\n" + "129\n" + "130\n" + "131\n" + "132\n" + "133\n" + "134\n" + "135\n" + "136\n" + "137\n" + "138\n" + "139\n" + "140\n" + "141\n" + "142\n" + "143\n" + "144\n" + "145\n" + "146\n" + "147\n" + "148\n" + "149\n" + "150\n" + "151\n" + "152\n" + "153\n" + "154\n" + "155\n" + "156\n" + "157\n" + "158\n" + "159\n" + "160\n" + "161\n" + "162\n" + "163\n" + "164\n" + "165\n" + "166\n" + "167\n" + "168\n" + "169\n" + "170\n" + "171\n" + "172\n" + "173\n" + "174\n" + "175\n" + "176\n" + "177\n" + "178\n" + "179\n" + "180\n" + "181\n" + "182\n" + "183\n" + "184\n" + "185\n" + "186\n" + "187\n" + "188\n" + "189\n" + "190\n" + "191\n" + "192\n" + "193\n" + "194\n" + "195\n" + "196\n" + "197\n" + "198\n" + "199\n" + "200\n" + "201\n" + "202\n" + "203\n" + "204\n" + "205\n" + "206\n" + "207\n" + "208\n" + "209\n" + "210\n" + "211\n" + "212\n" + "213\n" + "214\n" + "215\n" + "216\n" + "217\n" + "218\n" + "219\n" + "220\n" + "221\n" + "222\n" + "223\n" + "224\n" + "225\n" + "226\n" + "227\n" + "228\n" + "229\n" + "230\n" + "231\n" + "232\n" + "233\n" + "234\n" + "235\n" + "236\n" + "237\n" + "238\n" + "239\n" + "240\n" + "241\n" + "242\n" + "243\n" + "244\n" + "245\n" + "246\n" + "247\n" + "248\n" + "249\n" + "250\n" + "251\n" + "252\n" + "253\n" + "254\n" + "255\n" + "256\n" + "299\n" + "300\n" + "1000"; 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