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

r"
"
gm

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"LOG FORMAT.*\[(.*)\].*#" test_str = ("#KEEP THIS FILE IN THE SAME DIRECTORY AS __INIT.PY__, OTHERWISE IT WON'T WORK\n" " \n" "SETTINGS: \n" "FILE TO BE SORTED: \"C:\\Temp\\xmls - Copy\" #IF YOU ENTER \"in\" HERE THEN YOU CAN ENTER FILENAME FROM THE CONSOLE\n" "MINIMUM DISPLAY LEVEL OF LOGS: 10 #Warning = 30, Info = 20, Debug = 10, Notset = 0\n" "LOG DELIMITER SYMBOL: \"dupa\" #A SYMBOL WHICH SEPARATES THE LOG FORMAT MODULES\n" "FILE TO STORE LOGS: \"DEFAULT\" #TO CHANGE IT, PASTE FULL PATH OF THE CHOSEN DIRECTORY, RMEMBER TO PUT NAME.TXT AT THE END. DEFAULT = directory of __init.py__ \n" "LOG FORMAT: [LEVELNAME, ASCTIME, MESSAGE] #A FORMAT IN WHICH LOGS WILL BE STORED IN THE FILE (Surrounded by [] brackets)\n" "***\n" "LIST OF ATTRIBUTES:\n" "LEVELNAME, #Text logging level for the message ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL').\n" "ASCTIME, #Human-readable time when the LogRecord was created. By default this is of the form ‘2003-07-08 16:49:45,896’ (the numbers after the comma are millisecond portion of the time).\n" "MESSAGE, #The logged message, computed as msg % args.\n" "FUNCNAME, #Name of function containing the logging call.\n" "FILENAME, #Filename portion of pathname.\n" "PATHNAME, #Full pathname of the source file where the logging call was issued (if available).\n" "EMPTY #log will not be stored (IT SHOULD BE THE ONLY ONE MODULE IN THE LOG FORMAT)\n\n" "ADDITIONAL ATTRIBUTES:\n" "CREATED #Time when the LogRecord was created (as returned by time.time()).\n" "LEVELNO #Numeric logging level for the message (DEBUG, INFO, WARNING, ERROR, CRITICAL).\n" "LINENO #Source line number where the logging call was issued (if available).\n" "MODULE #Module (name portion of filename).\n" "MSECS #Millisecond portion of the time when the LogRecord was created.\n" "NAME #Name of the logger used to log the call.\n" "PROCESS #Process ID (if available).\n" "PROCESSNAME #Process name (if available).\n" "RELATIVECREATED #Time in milliseconds when the LogRecord was created, relative to the time the logging module was loaded.\n" "THREAD #Thread ID (NOT available)\n" "THREADNAME #Thread name (NOT available).\n" "***\n\n") matches = re.finditer(regex, test_str, 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