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

Language

Generated Code

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

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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx