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

const regex = new RegExp('Start\\W+([0-9]{2})', 'gm') const str = `'\\ufeffStore :,RS1 FAC_RS1 (South) ,Cashier :,2079 : Holly,Terminal :,2 : POS2 ,Receipt Number :,59450,Invoice Number :,RS102059450,Start :,01/01/2016 06:35:23 AM,End : ,01/01/2016 06:35:23 AM\\nItem ID,Receipt Alias,Quantity Sold,Unit Price,Extended Price,,,,,,,,,', 'Store :,RS1 FAC_RS1 (South) ,Cashier :,2138 : Mark,Terminal :,4 : POS4 ,Receipt Number :,59234,Invoice Number :,RS104059234,Start :,01/01/2016 06:41:41 AM,End : ,01/01/2016 06:41:41 AM\\nItem ID,Receipt Alias,Quantity Sold,Unit Price,Extended Price,,,,,,,,,', 'Store :,RS1 FAC_RS1 (South) ,Cashier :,2138 : Mark,Terminal :,3 : POS3 ,Receipt Number :,64407,Invoice Number :,RS103064407,Start :,01/01/2016 06:43:54 AM,End : ,01/01/2016 06:43:54 AM\\nItem ID,Receipt Alias,Quantity Sold,Unit Price,Extended Price,,,,,,,,,', 'Store :,RS1 FAC_RS1 (South) ,Cashier :,2138 : Mark,Terminal :,5 : POS5 ,Receipt Number :,64806,Invoice Number :,RS105064806,Start :,01/01/2016 06:46:21 AM,End : ,01/01/2016 06:46:21 AM\\nItem ID,Receipt Alias,Quantity Sold,Unit Price,Extended Price,,,,,,,,,', 'Store :,RS1 FAC_RS1 (South) ,Cashier :,1618 : Aron,Terminal :,6 : POS6 ,Receipt Number :,67963,Invoice Number :,RS106067963,Start :,01/01/2016 06:56:34 AM,End : ,01/01/2016 06:56:34 AM\\nItem ID,Receipt Alias,Quantity Sold,Unit Price,Extended Price,,,,,,,,,', 'Store :,RS1 FAC_RS1 (South) ,Cashier :,1618 : Aron,Terminal :,6 : POS6 ,Receipt Number :,67964,Invoice Number :,RS106067964,Start :,01/01/2016 07:20:35 AM,End : ,01/01/2016 07:21:04 AM\\nItem ID,Receipt Alias,Quantity Sold,Unit Price,Extended Price,,,,,,,,,\\n668,FA BRKFST WRAP,2.000,\$2.99,\$5.98,,,,,,,,,\\n102,COFFEE 12 OZ,1.000,\$1.50,\$1.50,,,,,,,,,', 'Store :,RS1 FAC_RS1 (South) ,Cashier :,1618 : Aron,Terminal :,6 : POS6 ,Receipt Number :,67964,Invoice Number :,RS106067964,Start :,01/01/2016 07:20:35 AM,End : ,01/01/2016 07:21:04 AM\\nItem ID,Receipt Alias,Quantity Sold,Unit Price,Extended Price,,,,,,,,,\\n,SUBTOTAL,,,\$7.48,,,,,,,,,\\n,TOTAL,,,\$7.48,,,,,,,,,\\n,TOTAL `; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions