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

/
/
gxm

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r""" ^(?<time>[^ +][-:0-9TZ]+|[[:upper:]][[:lower:]]{2}[ -:+0-9TZ]*)([^ ][+0:]+|\s+)(\s*)(?<host>[^ ][-\w\d]+)(\s*)(?<service>[^ [][-_\w]+)(\[(?<pid>[^ \]][\d]*)\]):\s*((\[\s*(?<mtime>[^ ][\w: \/]+)\]\s*\[\s*(?<severity>[^ ][\w]+)\]\s*){0,1}\s*\[\s*(?<component>[^ ][\w:]+)\]){0,1}\s*(?<message>.*){0,1}.*$ """ test_str = ("Oct 02 12:56:47 ctl01 td-agent-bit[22911]: [3915] haproxy: [1503580119.000000000, {\"path\"=>\"/var/log/sapmock/haproxy.log\", \"time\"=>\"2017-08-24T13:08:39\", \"host\"=>\"de4-1d-2d-0d-44-a0\", \"service\"=>\"ceilometer-polling\", \"message\"=>\"AMQP serve\n" "Oct 02 12:56:47 ctl01 td-agent-bit[22911]: [3916] haproxy: [1503580148.000000000, {\"path\"=>\"/var/log/sapmock/haproxy.log\", \"time\"=>\"2017-08-24T13:09:08\", \"host\"=>\"de4-1d-2d-0d-44-a0\", \"service\"=>\"ceilometer-polling\", \"message\"=>\"message re\n" "Oct 02 12:56:47 ctl01 td-agent-bit[22911]: [3917] haproxy: [1503580151.000000000, {\"path\"=>\"/var/log/sapmock/haproxy.log\", \"time\"=>\"2017-08-24T13:09:11\", \"host\"=>\"de4-1d-2d-0d-44-a0\", \"service\"=>\"ceilometer-polling\", \"message\"=>\"AMQP serve\n" "Oct 02 12:56:47 ctl01 td-agent-bit[22911]: [3918] haproxy: [1503580164.000000000, {\"path\"=>\"/var/log/sapmock/haproxy.log\", \"time\"=>\"2017-08-24T13:09:24\", \"host\"=>\"de4-1d-2d-0d-44-a0\", \"service\"=>\"ceilometer-polling\", \"message\"=>\"message re\n" "Oct 02 12:56:47 ctl01 td-agent-bit[22911]: [3919] haproxy: [1503580167.000000000, {\"path\"=>\"/var/log/sapmock/haproxy.log\", \"time\"=>\"2017-08-24T13:09:27\", \"host\"=>\"de4-1d-2d-0d-44-a0\", \"service\"=>\"ceilometer-polling\", \"message\"=>\"AMQP serve\n" "Oct 02 12:56:47 ctl01 td-agent-bit[22911]: [3920] haproxy: [1503580172.000000000, {\"path\"=>\"/var/log/sapmock/haproxy.log\", \"time\"=>\"2017-08-24T13:09:32\", \"host\"=>\"de4-1d-2d-0d-44-a0\", \"service\"=>\"ceilometer-polling\", \"message\"=>\"AMQP serve\n" "Oct 02 12:58:52 ctl01 td-agent-bit[22911]: [engine] caught signal\n" "Oct 02 12:58:52 ctl01 td-agent-bit[22911]: [2017/10/02 12:58:52] [ info] [input] pausing tail.0\n" "Oct 02 12:58:52 ctl01 td-agent-bit[22911]: [2017/10/02 12:58:52] [ info] [input] pausing tail.1\n" "Oct 02 12:58:52 ctl01 systemd[1]: Stopping TD Agent Bit...\n" "Oct 02 13:00:22 ctl01 systemd[1]: td-agent-bit.service: State 'stop-sigterm' timed out. Killing.\n" "Oct 02 13:00:22 ctl01 systemd[1]: td-agent-bit.service: Main process exited, code=killed, status=9/KILL\n" "Oct 02 13:00:22 ctl01 systemd[1]: Stopped TD Agent Bit.\n" "Oct 02 13:00:22 ctl01 systemd[1]: td-agent-bit.service: Unit entered failed state.\n" "Oct 02 13:00:22 ctl01 systemd[1]: td-agent-bit.service: Failed with result 'signal'.\n" "Oct 02 13:00:22 ctl01 systemd[1]: Started TD Agent Bit.\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [ info] [engine] started\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [error] [in_tail] parser 'rabbitmq' is not registered\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [ warn] [out_es] consider use a tag_key that starts with '_'\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [error] [parser:haproxy] Invalid time format %Y-%m-%dT%H:%M:%S.\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [error] [parser:haproxy] Invalid time format %Y-%m-%dT%H:%M:%S.\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [error] [parser:haproxy] Invalid time format %Y-%m-%dT%H:%M:%S.\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [error] [parser:haproxy] Invalid time format %Y-%m-%dT%H:%M:%S.\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [error] [parser:haproxy] Invalid time format %Y-%m-%dT%H:%M:%S.\n" "Oct 02 13:00:22 ctl01 td-agent-bit[23506]: [2017/10/02 13:00:22] [error] [parser:haproxy] Invalid time format %Y-%m-%dT%H:%M:%S.\n") matches = re.finditer(regex, test_str, re.VERBOSE | re.MULTILINE) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

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 Python, please visit: https://docs.python.org/3/library/re.html