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"\b(?:DE(?:\s*\d){20}|AT(?:\s*\d){18})\b(?!\s*\d)" test_str = ("################## Germany IBAN ##################\n" "DE59290501010001149590\n" "DE62500105179628448387\n" "DE55500105172374652131\n" "DE50500105176152274153\n\n" "DE 0712 3412 3412 3412 3412\n" "DE07 1234 1234 1234 1234 12\n" "DE07 1234 1234 1234 123412\n\n" "Mashine friendly DE07123412341234123412 style\n" "This format DE07 1234 1234 1234 1234 12 is given by DIN\n" "Human DE07 1234 1234 1234 123412 readable\n" "Not good DE07 12341234 1234123412 readable\n\n" "################## Austrian IBAN ##################\n" "AT59290501010001149590\n" "AT62500105179628448387\n" "AT55500105172374652131\n" "AT50500105176152274153\n\n" "AT 0712 3412 3412 3412 3412\n" "AT07 1234 1234 1234 1234 12\n" "AT07 1234 1234 1234 123412\n\n" "Mashine friendly AT07123412341234123412 style\n" "This format AT07 1234 1234 1234 1234 12 is given by DIN\n" "Human AT07 1234 1234 1234 123412 readable\n" "Not good AT07 12341234 1234123412 readable\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