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

/
/
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"Size: (?:\d*X[SL]|L|M|S|\d+W)(?:-(?:\d*X[LS]|L|M|S|\d+W))*," test_str = ("Athletics, Fitted, Mesh, Feature_Moisture Wicking, Material_Polyester 100%, , Material_Polyester 100%, Material_Polyester Over 50%, School, Style_Short Sleeves, Size_2XL, Size_L, Size_M, Size_S, Size_XL, Size_XS, Size: XS-S-M-L-XL-2XL, Uniforms, Unisex, V-Neck, VisibleLogos, Youth\n\n" "\"Weight_8-8.9oz, Adult, Age_Adult, Feature_Cotton-Combed, Embroidered, Fit_Mens, Apparel Type_Pants, Feature_Pockets, Material_Polyester 100%, , Material_Polyester Over 50%, Size: 32W, Size: 34W, Size: 36W, Size: 38W, Size: 40W, Size: 42W, Size: 44W, Size: 46W, Size: 48W, Size: 50W, Size: 50W-32W-34W-36W-38W-40W-42W-44W-46W-48W, Uniforms, Workwear\"\n\n" "\"Weight_5-5.9oz, Adult, Age_Adult, Feature_Cotton-Combed, Embroidered, Fit_Mens, Feature_Pockets, Material_Polyester 100%, , Material_Polyester Over 50%, Style_Short Sleeves, Size_2XL, Size_3XL, Size_4XL, Size_L, Size_M, Size_S, Size_XL, Uniforms, Workwear\"\n\n" "\"Weight_5-5.9oz, Adult, Age_Adult, Feature_Cotton-Combed, Syle_Long Sleeves, Fit_Mens, Feature_Pockets, Material_Polyester 100%, , Material_Polyester Over 50%, Size_2XLT, Size_LT, Size_LT-XLT-2XLT, Size_XLT, Talls, Uniforms, Workwear\"\n\n" "\"Weight_5-5.9oz, Adult, Age_Adult, Feature_Cotton-Combed, Embroidered, Syle_Long Sleeves, Fit_Mens, Feature_Pockets, Material_Polyester 100%, , Material_Polyester Over 50%, Size_2XL, Size_3XL, Size_4XL, Size_L, Size_M, Size_S, Size_XL, Uniforms, Workwear\"\n\n" "\"Weight_4-4.9oz, Adult, Age_Adult, Material_Cotton 100%, Feature_Cotton-Combed, Feature_Ringspun Cotton, Collar Style_Crewneck, Jersey, Fit_Juniors, Weight_Light(Under 5 oz), Material_Cotton 100%, Feature_No Visible Logos, Style_Short Sleeves, Feature_Side Seams, Feature_Side Seams, Size_2XL, Size_3XL, Size_L, Size_M, Size_S, Size_XL, Tag Style_Tear Away, Feature_USA Made, Womens\"\n\n" "\"Product Type_Accessories, Size_Adjustable, Adult, Age_Adult, Feature_American Made, Material_Cotton 100%, Material_Cotton Over 50%, Embroidered, GarmentWashed, Product Type_Headwear, Hat Styles_Low Profiles, Material_Cotton 100%, Feature_No Visible Logos, Hat Style_Pre-Curved Visor, Hat Style_Six Panel, Size_Size_Adjustable, UnHat Style_Structured, Feature_USA Certified, USAMade\"\n\n" "\"Product Type_Accessories, Size_Adjustable, Adult, Age_Adult, Feature_American Made, Material_Cotton 100%, Material_Cotton Over 50%, Embroidered, GarmentWashed, Product Type_Headwear, Hat Styles_Low Profiles, Material_Cotton 100%, Feature_No Visible Logos, Hat Style_Pre-Curved Visor, Style_Relaxed, Hat Style_Six Panel, Size_Size_Adjustable, UnHat Style_Structured, Feature_USA Certified, USAMade\"\n\n\n\n\n\n" "Size: 30W-40W,") 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