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

/
/
mg

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)(?<Date>\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}:\d{2})\s+(?<Type>\w+)\s\((?<Thread>[^\r\n]*)\)\s\[(?<Component>[^\r\n]*)]\s+(?<Message>[^\r\n]*)`) var str = `2018-11-08 19:36:30 DEBUG (MainThread) [homeassistant.components.websocket_api.http.connection.22795306331048] Sending {'id': 548, 'type': 'event', 'event': {'event_type': 'state_changed', 'data': {'entity_id': 'sun.sun', 'old_state': <state sun.sun=below_horizon; next_dawn=2018-11-09T06:54:59+00:00,next_dusk=2018-11-09T16:58:42+00:00,next_midnight=2018-11-08T23:56:54+00:00,next_noon=2018-11-09T11:56:50+00:00,next_rising=2018-11-09T07:35:52+00:00,next_setting=2018-11-09T16:17:49+00:00, elevation=-27.7, azimuth=280.88, friendly_name=Sun @ 2018-11-08T16:19:48.008546+00:00>, 'new_state': <state sun.sun=below_horizon; next_dawn=2018-11-09T06:54:59+00:00,next_dusk=2018-11-09T16:58:42+00:00,next_midnight=2018-11-08T23:56:54+00:00,next_noon=2018-11-09T11:56:50+00:00,next_rising=2018-11-09T07:35:52+00:00,next_setting=2018-11-09T16:17:49+00:00, elevation=-27.84, azimuth=281.1, friendly_name=Sun @ 2018-11-08T16:19:48.008546+00:00>}, 'origin': 'LOCAL', 'time_fired': datetime.datetime(2018, 11, 8, 19, 36, 30, 11522, tzinfo=<UTC>), 'context': {'id': '0ac682ff98424a2d970bc2f0fbd1683f','user_id': None}}}2018-11-08 19:36:30 DEBUG (Thread-6) [pychromecast.socket_client] connection listener: 14bbb1927b70 (CastStatusListener) 2018-11-08 19:36:30 DEBUG (Thread-6) [homeassistant.components.media_player.cast] Received cast device connection status: CONNECTING 2018-11-08 19:36:31 DEBUG (InfluxDB) [homeassistant.components.influxdb] Wrote 1 events 2018-11-08 19:36:32 DEBUG (SyncWorker_29) [mpd.base] Calling MPD status() 2018-11-08 19:36:32 DEBUG (SyncWorker_29) [mpd.base] Calling MPD currentsong() ` for i, match := range re.FindAllString(str, -1) { fmt.Println(match, "found at index", 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 Golang, please visit: https://golang.org/pkg/regexp/