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

/
/

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"air_temp"": ([\d.]+)"; string input = @" { ""observations"": { ""notice"": [ { ""copyright"": ""Copyright Commonwealth of Australia 2017, Bureau of Meteorology. For more information see: http://www.bom.gov.au/other/copyright.shtml http://www.bom.gov.au/other/disclaimer.shtml"", ""copyright_url"": ""http://www.bom.gov.au/other/copyright.shtml"", ""disclaimer_url"": ""http://www.bom.gov.au/other/disclaimer.shtml"", ""feedback_url"": ""http://www.bom.gov.au/other/feedback"" } ], ""header"": [ { ""refresh_message"": ""Issued at 12:11 pm EST Tuesday 11 July 2017"", ""ID"": ""IDN60901"", ""main_ID"": ""IDN60902"", ""name"": ""Canberra"", ""state_time_zone"": ""NSW"", ""time_zone"": ""EST"", ""product_name"": ""Capital City Observations"", ""state"": ""Aust Capital Territory"" } ], ""data"": [ { ""sort_order"": 0, ""wmo"": 94926, ""name"": ""Canberra"", ""history_product"": ""IDN60903"", ""local_date_time"": ""11/12:00pm"", ""local_date_time_full"": ""20170711120000"", ""aifstime_utc"": ""20170711020000"", ""lat"": -35.3, ""lon"": 149.2, ""apparent_t"": 5.7, ""cloud"": ""Mostly clear"", ""cloud_base_m"": 1050, ""cloud_oktas"": 1, ""cloud_type_id"": 8, ""cloud_type"": ""Cumulus"", ""delta_t"": 3.6, ""gust_kmh"": 11, ""gust_kt"": 6, ""air_temp"": 9.0, ""dewpt"": 0.2, ""press"": 1032.7, ""press_qnh"": 1031.3, ""press_msl"": 1032.7, ""press_tend"": ""-"", ""rain_trace"": ""0.0"", ""rel_hum"": 54, ""sea_state"": ""-"", ""swell_dir_worded"": ""-"", ""swell_height"": null, ""swell_period"": null, ""vis_km"": ""10"", ""weather"": ""-"", ""wind_dir"": ""WNW"", ""wind_spd_kmh"": 7, ""wind_spd_kt"": 4 }, { ""sort_order"": 1, ""wmo"": 94926, ""name"": ""Canberra"", ""history_product"": ""IDN60903"", ""local_date_time"": ""11/11:30am"", ""local_date_time_full"": ""20170711113000"", ""aifstime_utc"": ""20170711013000"", ""lat"": -35.3, ""lon"": 149.2, ""apparent_t"": 4.6, ""cloud"": ""Mostly clear"", ""cloud_base_m"": 900, ""cloud_oktas"": 1, ""cloud_type_id"": 8, ""cloud_type"": ""Cumulus"", ""delta_t"": 2.9, ""gust_kmh"": 9, ""gust_kt"": 5, ""air_temp"": 7.3, ""dewpt"": 0.1, ""press"": 1033.1, ""press_qnh"": 1031.7, ""press_msl"": 1033.1, ""press_tend"": ""-"", ""rain_trace"": ""0.0"", ""rel_hum"": 60, ""sea_state"": ""-"", ""swell_dir_worded"": ""-"", ""swell_height"": null, ""swell_period"": null, ""vis_km"": ""10"", ""weather"": ""-"", ""wind_dir"": ""NW"", ""wind_spd_kmh"": 4, ""wind_spd_kt"": 2 } ] } }"; Match m = Regex.Match(input, pattern); 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