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

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /\{"app_id":"(?P<appid>(?:\w+))","dev_id":"(?P<devid>(?:\w+))","hardware_serial":"(?P<hardwareserial>(?:\w+))","port":(?P<port>(?:\d+)),"counter":(?P<counter>(?:\d+)),"payload_raw":"(?P<raw>(?:(\w+\=|\w+|\w+\==)))","payload_fields":{"(?P<value>(?:\w+))":"(?P<val>(?:\d+))"},"metadata":{"time":"(?P<time>(?:\w+-\w+-\w+:\w+:\w+.\w+))","frequency":(?P<freq>(?:(\w+.*\w+|\d+))),"modulation":"(?P<modulation>(?:\w+))","data_rate":"(?P<data_rate>(?:\w+))","airtime":(?P<airtime>(?:\w+)),"coding_rate":"(?P<coding_rate>(?:\d+\/\w+))","gateways":\[{"gtw_id":"(?P<gtw_id>(?:(\w+|\w+\-\w+)))"(|,"gtw_trusted":(?P<trusted>(?:\w+))),"timestamp":(?P<timestamp>(?:\w+)),"time":"(?P<times>(?:(\w+.\w+.\w+.\w+.\w+|\w+.\w+.\w+.\w+.\w+.\w+)))","channel":(?P<channel>(?:\d+)),"rssi":-(?P<rssi>(?:\d+)),"snr":(?P<snr>(?:(\d+.\d+|\d+))),"rf_chain":(?P<rf_chain>(?:\d+)),"latitude":(?P<latitude>(?:(\d+.\d+|\d+))),"longitude":(?P<longitude>(?:\b(\d*.\d+|\d)\b)),"location_source":"(?P<registry>(?:\w+))"}\]}}/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\{"app_id":"(?P<appid>(?:\\w+))","dev_id":"(?P<devid>(?:\\w+))","hardware_serial":"(?P<hardwareserial>(?:\\w+))","port":(?P<port>(?:\\d+)),"counter":(?P<counter>(?:\\d+)),"payload_raw":"(?P<raw>(?:(\\w+\\=|\\w+|\\w+\\==)))","payload_fields":{"(?P<value>(?:\\w+))":"(?P<val>(?:\\d+))"},"metadata":{"time":"(?P<time>(?:\\w+-\\w+-\\w+:\\w+:\\w+.\\w+))","frequency":(?P<freq>(?:(\\w+.*\\w+|\\d+))),"modulation":"(?P<modulation>(?:\\w+))","data_rate":"(?P<data_rate>(?:\\w+))","airtime":(?P<airtime>(?:\\w+)),"coding_rate":"(?P<coding_rate>(?:\\d+\\\/\\w+))","gateways":\\[{"gtw_id":"(?P<gtw_id>(?:(\\w+|\\w+\\-\\w+)))"(|,"gtw_trusted":(?P<trusted>(?:\\w+))),"timestamp":(?P<timestamp>(?:\\w+)),"time":"(?P<times>(?:(\\w+.\\w+.\\w+.\\w+.\\w+|\\w+.\\w+.\\w+.\\w+.\\w+.\\w+)))","channel":(?P<channel>(?:\\d+)),"rssi":-(?P<rssi>(?:\\d+)),"snr":(?P<snr>(?:(\\d+.\\d+|\\d+))),"rf_chain":(?P<rf_chain>(?:\\d+)),"latitude":(?P<latitude>(?:(\\d+.\\d+|\\d+))),"longitude":(?P<longitude>(?:\\b(\\d*.\\d+|\\d)\\b)),"location_source":"(?P<registry>(?:\\w+))"}\\]}}', 'gm') const str = ``; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions