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

r"
"
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 = "\\[[+-]?([048]|\\d*([02468][048]|[13579][26]))\\]"; final String string = "\"[+05620]\" // 5620 is divisible by 4 (valid)\n" + "\"[+05621]\" // 5621 is not divisible by 4 (invalid)\n" + "\"[-55622]\" // -55622 is not divisible by 4 (invalid)\n" + "\"[005623]\" // 5623 invalid\n" + "\"[005624]\" // 5624 valid\n" + "\"[-05628]\" // valid\n" + "\"[005632]\" // valid\n" + "\"[555636]\" // valid\n" + "\"[+05640]\" // valid\n" + "\"[005600]\" // valid\n" + "\"[8.04]\" // invalid\n" + "\"[8.00]\" // valid\n\n" + "\"[-0]\"\n" + "\"...may be [+002016] will be.\"\n\n" + "\"[+05621]\", \"[-55622]\", \n" + "\"[005623]\", \"[~24]\", \"[8.04]\", \n" + "\"No, [2014] isn't a multiple of 4...\"\n\n" + "\"[0]\"\n" + "\"[4]\"\n" + "\"[8]\"\n" + "\"[12]\"\n" + "\"[16]\"\n" + "\"[20]\"\n" + "\"[24]\"\n" + "\"[28]\"\n" + "\"[32]\"\n" + "\"[36]\"\n" + "\"[40]\"\n" + "\"[44]\"\n" + "\"[48]\"\n" + "\"[52]\"\n" + "\"[56]\"\n" + "\"[60]\"\n" + "\"[64]\"\n" + "\"[68]\"\n" + "\"[72]\"\n" + "\"[76]\"\n" + "\"[80]\"\n" + "\"[84]\"\n" + "\"[88]\"\n" + "\"[92]\"\n" + "\"[96]\"\n" + "\"[100]\"\n" + "\"[104]\"\n" + "\"[108]\"\n" + "\"[112]\"\n" + "\"[116]\"\n" + "\"[120]\"\n" + "\"[124]\"\n" + "\"[128]\"\n\n" + "\"[1]\"\n" + "\"[2]\"\n" + "\"[3]\"\n" + "\"[5]\"\n" + "\"[6]\"\n" + "\"[7]\"\n" + "\"[9]\"\n" + "\"[10]\"\n" + "\"[11]\"\n" + "\"[13]\"\n" + "\"[14]\"\n" + "\"[15]\"\n" + "\"[17]\"\n" + "\"[18]\"\n" + "\"[19]\"\n" + "\"[21]\"\n" + "\"[22]\"\n" + "\"[23]\"\n" + "\"[25]\"\n" + "\"[26]\"\n" + "\"[27]\"\n" + "\"[29]\"\n" + "\"[30]\"\n" + "\"[31]\"\n" + "\"[33]\"\n" + "\"[34]\"\n" + "\"[35]\"\n" + "\"[37]\"\n" + "\"[38]\"\n" + "\"[39]\"\n" + "\"[41]\"\n" + "\"[42]\"\n" + "\"[43]\"\n" + "\"[45]\"\n" + "\"[46]\"\n" + "\"[47]\"\n" + "\"[49]\"\n" + "\"[50]\"\n" + "\"[51]\"\n" + "\"[53]\"\n" + "\"[54]\"\n" + "\"[55]\"\n" + "\"[57]\"\n" + "\"[58]\"\n" + "\"[59]\"\n" + "\"[61]\"\n" + "\"[62]\"\n" + "\"[63]\"\n" + "\"[65]\"\n" + "\"[66]\"\n" + "\"[67]\"\n" + "\"[69]\"\n" + "\"[70]\"\n" + "\"[71]\"\n" + "\"[73]\"\n" + "\"[74]\"\n" + "\"[75]\"\n" + "\"[77]\"\n" + "\"[78]\"\n" + "\"[79]\"\n" + "\"[81]\"\n" + "\"[82]\"\n" + "\"[83]\"\n" + "\"[85]\"\n" + "\"[86]\"\n" + "\"[87]\"\n" + "\"[89]\"\n" + "\"[90]\"\n" + "\"[91]\"\n" + "\"[93]\"\n" + "\"[94]\"\n" + "\"[95]\"\n" + "\"[97]\"\n" + "\"[98]\"\n" + "\"[99]\"\n" + "\"[101]\"\n" + "\"[102]\"\n" + "\"[103]\"\n" + "\"[105]\"\n" + "\"[106]\"\n" + "\"[107]\"\n" + "\"[109]\"\n" + "\"[110]\"\n" + "\"[111]\"\n" + "\"[113]\"\n" + "\"[114]\"\n" + "\"[115]\"\n" + "\"[117]\"\n" + "\"[118]\"\n" + "\"[119]\"\n" + "\"[121]\"\n" + "\"[122]\"\n" + "\"[123]\"\n" + "\"[125]\"\n" + "\"[126]\"\n" + "\"[127]\"\n" + "\"[129]\"\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n" + "0\n" + "4\n" + "8\n" + "12\n" + "16\n" + "20\n" + "24\n" + "28\n" + "32\n" + "36\n" + "40\n" + "44\n" + "48\n" + "52\n" + "56\n" + "60\n" + "64\n" + "68\n" + "72\n" + "76\n" + "80\n" + "84\n" + "88\n" + "92\n" + "96\n" + "100\n" + "104\n" + "108\n" + "112\n" + "116\n" + "120\n" + "124\n" + "128\n\n" + "1\n" + "2\n" + "3\n" + "5\n" + "6\n" + "7\n" + "9\n" + "10\n" + "11\n" + "13\n" + "14\n" + "15\n" + "17\n" + "18\n" + "19\n" + "21\n" + "22\n" + "23\n" + "25\n" + "26\n" + "27\n" + "29\n" + "30\n" + "31\n" + "33\n" + "34\n" + "35\n" + "37\n" + "38\n" + "39\n" + "41\n" + "42\n" + "43\n" + "45\n" + "46\n" + "47\n" + "49\n" + "50\n" + "51\n" + "53\n" + "54\n" + "55\n" + "57\n" + "58\n" + "59\n" + "61\n" + "62\n" + "63\n" + "65\n" + "66\n" + "67\n" + "69\n" + "70\n" + "71\n" + "73\n" + "74\n" + "75\n" + "77\n" + "78\n" + "79\n" + "81\n" + "82\n" + "83\n" + "85\n" + "86\n" + "87\n" + "89\n" + "90\n" + "91\n" + "93\n" + "94\n" + "95\n" + "97\n" + "98\n" + "99\n" + "101\n" + "102\n" + "103\n" + "105\n" + "106\n" + "107\n" + "109\n" + "110\n" + "111\n" + "113\n" + "114\n" + "115\n" + "117\n" + "118\n" + "119\n" + "121\n" + "122\n" + "123\n" + "125\n" + "126\n" + "127\n" + "129"; 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