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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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

/
/
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((?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(?:(?<!\.)\b|\.)){4}" test_str = ("#Ejemplos de codigo fuente del lenguaje de programacion Ruby\n\n" "#Aritmetica basica\n" "resultado='5 * (12 - 8) + -15'\n" "puts resultado\n" "puts 98 + (59872 / (13 * 8)) * -52\n\n" "#Textos\n" "puts \"Hola, mundo!\"\n" "puts \"\"\n" "puts \"Adiós.\"\n" "puts \"Me gusta\" + \"el pastel de manzana.\"\n" "puts \"Mi IP es: 192.168.9.10\"\n" "puts \"ragustin726@gmail.com\"\n" "puts \"https://www.facebook.com\"\n" "puts \"31/01/2021/\"\n\n" "277.893.21.2\n\n" "#Variables\n" "myString = '...puedes decir eso de nuevo...'\n" "puts myString\n" "name = 'Patricia Rosanna Jessica Mildred Oppenheimer'\n" "ip= 10.0.0.1\n" "correo='roberto_840@hotmail.com'\n" "direccion='https://www.google.com'\n" "fecha = '19/07/2001'\n\n" "#Concatenaciones\n" "puts 'Me llamo ' + name + '.'\n" "puts 'Wow! \"' + name + '\" es un nombre realmente largo!'\n" "composer1 = 'Mozart'\n" "puts composer1 + ' fue \"el amo\", en su día.'\n" "composer = 'Beethoven'\n" "puts 'Pero yo prefiero a ' + composer1 + ', personalmente.'\n\n" "#Conversiones\n" "var1 = 2\n" "var2 = '5'\n" "puts var1.to_s + var2\n" "var1 = 2\n" "var2 = '5'\n" "puts var1.to_s + var2\n" "puts var1 + var2.to_i\n\n" "#Condicionales \n" "puts 1 > 2\n" "puts 1 < 2\n" "puts 5 >= 5\n" "puts 5 <= 4\n" "puts 1 == 1\n" "puts 2 != 1\n" "puts 'gato' < 'perro'\n\n" "#Ramificaciones\n" "puts 'Hola, y bienvenido a la clase de 7mo año.'\n" "puts 'Me llamo Mrs. Gabbard. ¿Tú nombre es...?'\n" "nombre = gets.chomp\n\n" "if nombre == nombre.capitalize\n" " puts 'Por favor, toma asiento ' + nombre + '.'\n" "else\n" " puts '¿' + nombre + '? Quieres decir ' + nombre.capitalize + ', ¿cierto?'\n" " puts '¿No sabes escribir tu propio nombre?'\n" " respuesta = gets.chomp\n\n" " if respuesta.downcase == 'si'\n" " puts '¡Hum! Bueno, ¡siéntese!'\n" " else\n" " puts '¡SALGA DEL SALON!'\n" " end\n" "end\n\n" "#Bucles\n" "comando = ''\n" "while comando != 'adios'\n" " puts comando\n" " comando = gets.chomp\n" "end\n" "puts '¡Vuelve pronto!'\n\n" "#Operadores logicos\n" "edad=18\n" "sexo=\"Mujer\"\n" "ocupacion=\"Estudiante\"\n" "if edad>=18 and sexo==\"Mujer\" and ocupacion=\"Estudiante\"\n" " puts \"Mujer mayor de edad estudiante\"\n" "end\n\n" "edad=18\n" "if edad>=18 or edad<=25\n" " puts \"Tu edad esta entre los 18 y 25 años\"\n" "end\n\n" "#Modulos y potencias\n" "puts 5**2\n" "puts 5**0.5\n" "puts 7/3\n" "puts 7%3\n" "puts 365%7\n\n" "#Lectura de archivos\n" "content1 = File.read(\"imagen.jpg\") # lee el archivo\n" "content2 = File.read(\"contenido.png\")\n" "lines = content.split(\"\\n\") # divide el contenido en líneas\n\n" "# recorre las líneas y las imprime\n" "lines.each do |line|\n" " puts line\n" "end") 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