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

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