Download - The Bastards Book of Regular Expressions

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Optionality and alternation 97they'retheyretheirthereAnswerFind the[iry]'?[er]Note: while this is an amusing exercise, this regex is so unreadable that you’re better off just usingstraight-up alternation:their|there|they'?reExercise: Zip codesIn the United States, zip codes can come in at least two different forms: five-digit and nine-digit:10020-90201001860201-3277In the following city listings, add commas to delimit the state, zip code, and country information.Change:New York 10020-9020 United StatesCalifornia 90210 U.S.To:New York, 10020-9020, United StatesCalifornia, 90210, U.S.AnswerThe optional part of the pattern is the hyphen and the four numerical digits:Find ( \d{5})(-\d{4})?Replace ,\1\2,
Optionality and alternation 98You might wonder what the second capturing group captures if nothing is actually there, as in thecase of California 90210 U.S., in which the optional pattern doesn’t exist. For our purposes,nothing is captured in that second group and nothing is thus affected by it.But again, you should be using non-capturing parentheses as possible. Here’s an alternate solution:Find ( \d{5}(?:-\d{4})?)Replace ,\1,If it hasn’t hit you by now, regular expressions are extremely useful in finding terms and datapointswhen you don’t quite know what they look like. The alternation and optionality operators make iteven more convenient to add flexibility to our searches.
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The Bastards Book ofRegular Express
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CONTENTSOptionality and alternation
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CONTENTSSwitching visualizations (T
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Regular Expressions are for Everyon
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Regular Expressions are for Everyon
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Getting Started6
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Finding a proper text editor 8Notep
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Finding a proper text editor 10Edit
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Finding a proper text editor 12Text
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Finding a proper text editor 14does
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Finding a proper text editor 16Yest
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Finding a proper text editor 18A do
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A better Find-and-Replace 20The lim
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A better Find-and-Replace 22Using R
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Your first regex 24helloThe Find-an
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Your first regex 26The regex syntax
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Your first regex 28Double-bounded
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Your first regex 30AnswerFind \bcat
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Removing emptinessIt’s funny how
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Removing emptiness 34Now let’s do
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Removing emptiness 36…as opposed
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Removing emptiness 38Replacement in
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Match one-or-more with the plus sig
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Page 53 and 54: Match one-or-more with the plus sig
Page 55 and 56: Match zero-or-more with the star si
Page 57 and 58: Specific and limited repetition 501
Page 59 and 60: Specific and limited repetition 52E
Page 61 and 62: Specific and limited repetition 54C
Page 63 and 64: Anchors: A way to trim emptinessIn
Page 65 and 66: Anchors: A way to trim emptiness 58
Page 71 and 72: Matching any letter, any number 64A
Page 73 and 74: Matching any letter, any number 66W
Page 75 and 76: Matching any letter, any number 68[
Page 77 and 78: Matching any letter, any number 70R
Page 79 and 80: Matching any letter, any number 72F
Page 81 and 82: Matching any letter, any number 74A
Page 83 and 84: Negative character sets 76$1,200.00
Page 85 and 86: Negative character sets 78\W+Exerci
Page 87 and 88: Capture, Reuse 80Find (ba)+Matches
Page 89 and 90: Capture, Reuse 82.- then the 1st ba
Page 91 and 92: Capture, Reuse 84In English We are
Page 93 and 94: Capture, Reuse 86ApplesOraclesOrang
Page 95 and 96: Capture, Reuse 8805-14-8912-03-9803
Page 97 and 98: Capture, Reuse 90Mary asked: "What
Page 99 and 100: Optionality and alternationThe two
Page 101 and 102: Optionality and alternation 94Answe
Page 103: Optionality and alternation 96Studi
Page 107 and 108: Laziness and greediness 100Being to
Page 109 and 110: Laziness and greediness 102Replace
Page 111 and 112: Laziness and greediness 104With the
Page 113 and 114: Lookarounds 106cat(?=s)- will match
Page 115 and 116: Lookarounds 108`(?
Page 117 and 118: Lookarounds 110ExerciseGiven the fo
Page 119 and 120: Lookarounds 112City,CountryAlbuquer
Page 121 and 122: Lookarounds 114Given this list of c
Page 123 and 124: Lookarounds 116100,J.D. Salinger Av
Page 125 and 126: Lookarounds 1186,300|Apples|New Yor
Page 127 and 128: Lookarounds 120^(\d+) Record ID (\w
Page 129 and 130: Lookarounds 122d. Remove all asides
Page 131 and 132: From Data to HTML (TODO)This chapte
Page 133 and 134: From Data to HTML (TODO) 126Turning
Page 135 and 136: The ExercisesI’ve never been one
Page 137 and 138: Data Cleaning with the Stars 130LOR
Page 139 and 140: Data Cleaning with the Stars 132[GM
Page 141 and 142: Finding needles in haystacks (TODO)
Page 143 and 144: Changing phone format (TODO)Todo: T
Page 145 and 146: Changing phone format (TODO) 138Exe
Page 147 and 148: Changing phone format (TODO) 140Ans
Page 149 and 150: Changing phone format (TODO) 142`1-
Page 151 and 152: Changing phone format (TODO) 144(\d
Page 153 and 154: Dating, Associated Press Style (TOD
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Dating, Associated Press Style (TOD
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Sorting a police blotter 154Sloppy
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Sorting a police blotter 156I used
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Converting XML to tab-delimited dat
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Converting XML to tab-delimited dat
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Cleaning up Microsoft Word HTML(TOD
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Cleaning up OCR Text (TODO)Image sc
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Moving forwardThank you for taking
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