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

/
/
gmi

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"^\s*[a-zA-Z]{1}[0-9a-zA-Z][0-9a-zA-Z '-.=#/]*$" test_str = ("test=123\n" "=test123\n" "austin .,#/-\n" "Aberdeen\n" "Abilene\n" "Akron\n" "Albany\n" "Albu querque\n" "Alexandria\n" "Allentown\n" "Amarillo\n" "Anaheim\n" "Anchorage\n" "Ann Arbor\n" "Antioch\n" "Apple Valley\n" "Appleton\n" "Arlington\n" "Arvada\n" "Asheville\n" "Athens\n" "Atlanta\n" "Atlantic City\n" "Augusta\n" "Aurora\n" "Austin\n" "Bakersfield\n" "Baltimore\n" "Barnstable\n" "Baton Rouge\n" "Beaumont\n" "Bel Air\n" "Bellevue\n" "Berkeley\n" "Bethlehem\n" "Billings\n" "Birmingham\n" "Bloomington\n" "Boise\n" "Boise City\n" "Bonita Springs\n" "Boston\n" "Boulder\n" "Bradenton\n" "Bremerton\n" "Bridgeport\n" "Brighton\n" "Brownsville\n" "Bryan\n" "Buffalo\n" "Burbank\n" "Burlington\n" "Cambridge\n" "Canton\n" "Cape Coral\n" "Carrollton\n" "Cary\n" "Cathedral City\n" "Cedar Rapids\n" "Champaign\n" "Chandler\n" "Charleston\n" "Charlotte\n" "Chattanooga\n" "Chesapeake\n" "Chicago\n" "Chula Vista\n" "Cincinnati\n" "Clarke County\n" "Clarksville\n" "Clearwater\n" "Cleveland\n" "College Station\n" "Colorado Springs\n" "Columbia\n" "Columbus\n" "Concord\n" "Coral Springs\n" "Corona\n" "Corpus Christi\n" "Costa Mesa\n" "Dallas\n" "Daly City\n" "Danbury\n" "Davenport\n" "Davidson County\n" "Dayton\n" "Daytona Beach\n" "Deltona\n" "Denton\n" "Denver\n" "Des Moines\n" "Detroit\n" "Downey\n" "Duluth\n" "Durham\n" "El Monte\n" "El Paso\n" "Elizabeth\n" "Elk Grove\n" "Elkhart\n" "Erie\n" "Escondido\n" "Eugene\n" "Evansville\n" "Fairfield\n" "Fargo\n" "Fayetteville\n" "Fitchburg\n" "Flint\n" "Fontana\n" "Fort Collins\n" "Fort Lauderdale\n" "Fort Smith\n" "Fort Walton Beach\n" "Fort Wayne\n" "Fort Worth\n" "Frederick\n" "Fremont\n" "Fresno\n" "Fullerton\n" "Gainesville\n" "9Garden Grove\n" "Garland\n" "Gastonia\n" "Gilbert\n" "Glendale\n" "Grand Prairie\n" "Grand Rapids\n" "Grayslake\n" "Green Bay\n" "GreenBay\n" "Greensboro\n" "Greenville\n" "Gulfport-Biloxi\n" "Hagerstown\n" "Hampton\n" "Harlingen\n" "Harrisburg\n" "Hartford\n" "Havre de Grace\n" "Hayward\n" "Hemet\n" "Henderson\n" "Hesperia\n" "Hialeah\n" "Hickory\n" "High Point\n" "Hollywood\n" "Honolulu\n" "Houma\n" "Houston\n" "Howell\n" "Huntington\n" "Huntington Beach\n" "Huntsville\n" "Independence\n" "Indianapolis\n" "Inglewood\n" "Irvine\n" "Irving\n" "Jackson\n" "Jacksonville\n" "Jefferson\n" "Jersey City\n" "Johnson City\n" "Joliet\n" "Kailua\n" "Kalamazoo\n" "Kaneohe\n" "Kansas City\n" "Kennewick\n" "Kenosha\n" "Killeen\n" "Kissimmee\n" "Knoxville\n" "Lacey\n" "Lafayette\n" "Lake Charles\n" "Lakeland\n" "Lakewood\n" "Lancaster\n" "Lansing\n" "Laredo\n" "Las Cruces\n" "Las Vegas\n" "Layton\n" "Leominster\n" "Lewisville\n" "Lexington\n" "Lincoln\n" "Little Rock\n" "Long Beach\n" "Lorain\n" "Los Angeles\n" "Louisville\n" "Lowell\n" "Lubbock\n" "Macon\n" "Madison\n" "Manchester\n" "Marina\n" "Marysville\n" "McAllen\n" "McHenry\n" "Medford\n" "Melbourne\n" "Memphis\n" "Merced\n" "Mesa\n" "Mesquite\n" "Miami\n" "Milwaukee\n" "Minneapolis\n" "Miramar\n" "Mission Viejo\n" "Mobile\n" "Modesto\n" "Monroe\n" "Monterey\n" "Montgomery\n" "Moreno Valley\n" "Murfreesboro\n" "Murrieta\n" "Muskegon\n" "Myrtle Beach\n" "Naperville\n" "Naples\n" "Nashua\n" "Nashville\n" "New Bedford\n" "New Haven\n" "New London\n" "New Orleans\n" "New York\n" "New York City\n" "Newark\n" "Newburgh\n" "Newport News\n" "Norfolk\n" "Normal\n" "Norman\n" "North Charleston\n" "North Las Vegas\n" "North Port\n" "Norwalk\n" "Norwich\n" "Oakland\n" "Ocala\n" "Oceanside\n" "Odessa\n" "Ogden\n" "Oklahoma City\n" "Olathe\n" "Olympia\n" "Omaha\n" "Ontario\n" "Orange\n" "Orem\n" "Orlando\n" "Overland Park\n" "Oxnard\n" "Palm Bay\n" "Palm Springs\n" "Palmdale\n" "Panama City\n" "Pasadena\n" "Paterson\n" "Pembroke Pines\n" "Pensacola\n" "Peoria\n" "Philadelphia\n" "Phoenix\n" "Pittsburgh\n" "Plano\n" "Pomona\n" "Pompano Beach\n" "Port Arthur\n" "Port Orange\n" "Port Saint Lucie\n" "Port St. Lucie\n" "Portland\n" "Portsmouth\n" "Poughkeepsie\n" "Providence\n" "Provo\n" "Pueblo\n" "Punta Gorda\n" "Racine\n" "Raleigh\n" "Rancho Cucamonga\n" "Reading\n" "Redding\n" "Reno\n" "Richland\n" "Richmond\n" "Richmond County\n" "Riverside\n" "Roanoke\n" "Rochester\n" "Rockford\n" "Roseville\n" "Round Lake Beach\n" "Sacramento\n" "Saginaw\n" "Saint Louis\n" "Saint Paul\n" "Saint Petersburg\n" "Salem\n" "Salinas\n" "Salt Lake City\n" "San Antonio\n" "San Bernardino\n" "San Buenaventura\n" "San Diego\n" "San Francisco\n" "San Jose\n" "Santa Ana\n" "Santa Barbara\n" "Santa Clara\n" "Santa Clarita\n" "Santa Cruz\n" "Santa Maria\n" "Santa Rosa\n" "Sarasota\n" "Savannah\n" "Scottsdale\n" "Scranton\n" "Seaside\n" "Seattle\n" "Sebastian\n" "Shreveport\n" "Simi Valley\n" "Sioux City\n" "Sioux Falls\n" "South Bend\n" "South Lyon\n" "Spartanburg\n" "Spokane\n" "Springdale\n" "Springfield\n" "St. Louis\n" "St. Paul\n" "St. Petersburg\n" "Stamford\n" "Sterling Heights\n" "Stockton\n" "Sunnyvale\n" "Syracuse\n" "Tacoma\n" "Tallahassee\n" "Tampa\n" "Temecula\n" "Tempe\n" "Thornton\n" "Thousand Oaks\n" "Toledo\n" "Topeka\n" "Torrance\n" "Trenton\n" "Tucson\n" "Tulsa\n" "Tuscaloosa\n" "Tyler\n" "Utica\n" "Vallejo\n" "Vancouver\n" "Vero Beach\n" "Victorville\n" "Virginia Beach\n" "Visalia\n" "Waco\n" "Warren\n" "Washington\n" "Waterbury\n" "Waterloo\n" "West Covina\n" "West Valley City\n" "Westminster\n" "Wichita\n" "Wilmington\n" "Winston\n" "Winter Haven\n" "Worcester\n" "Yakima\n" "Yonkers\n" "York\n" "Youngstown") matches = re.finditer(regex, test_str, re.MULTILINE | re.IGNORECASE) 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