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"(degree(s)? of)(\n?|.+?)(\w.+|\w?.+\n.+)" test_str = ("MIT Sample:\n" "AN EXPERIMENTAL INVESTIGATION OF\n" "OIL SPREADING OVER WATER\n" "by\n" "Walter Suchon\n" "Submitted in Partial Fulfillment\n" "of the Requirements for the\n" "degrees of\n" "bachelor of science\n" "and\n" "Master of Science\n" "at the\n" "MASSACHUSETTS INSTITUTE OF TECHNOLOGY\n" "April, 1970\n" "Signature of Author\n" "Department of Mechanical Engineering\n" "Certified by.......\n" "Thesis Supervisor\n" "Accepted by\n" "Chairman, Departmental Committee on Graduate Students\n" "Archives\n" "MASS INST. TECH.\n" "SEP 10 1970\n" "LIBRARIES\n" "--------------------------------------------------------------\n" "Virginia Tech Sample:\n" "FUNDAMENTAL ADHESIVE STUDIES OF BLOCK COPOLYMERS\n" "by\n" "Margaret Mary Sheridan\n" "Dissertation submitted to the Faculty of the\n" "Virginia Polytechnic Institute and State University\n" "in partial fulfillment of the requirements for the degree of\n" "Doctor of Philosophy\n" "in\n" "Chemistry\n" "APPROVED:\n" "T.C. Ward, Chairman\n" "D.W. Dwight M.A. Oglioruso\n" "J.E. McGrath J.P. Wightman\n" "October, 1985\n" "Blacksburg, Virginia") 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