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Lookarounds 1153. City: A combination of word characters (actually, just letters) and spaces until a comma isreached.4. State: Two uppercase letters5. Zip: Five consecutive digitsFind ˆ(\d+) ([\w ]+\.) ([\w ]+), ([A-Z]{2}) (\d{5})Replace \1,\2,\3,\4,\5Exercise: Complicated street names Street address lists can get way more complicated than this,of course. The following exercise tests how well you understand the differences between [lazinessand greediness]{#laziness}..Note: Don’t fret if you don’t get this. Fully grokking this kind of exercise requires betterunderstanding of what’s going on under the hood, which is what I’ve avoided presenting sofar. Regular-expressions.info has a great lesson on the internals.TKWhat if our list of street names had periods within them?100 J.D. Salinger Ave. City, ST 9999942 J.F.K. Blvd. New York, NY 10555Then the pattern for a street name would consist more of just word characters and spaces until aliteral period.So this is the pattern we have to alter:([\w ]+\.)Now a simple solution may be just to include the literal dot inside the character set, like so:([\w .]+)Find ˆ(\d+) ([\w .]+) ([\w ]+), ([A-Z]{2}) (\d{5})Replace \1\2\3\4\5And that kind of works:
Lookarounds 116100,J.D. Salinger Ave.,City,ST,9999942,J.F.K. Blvd. New,York,NY,10555But notice the improper delimitation in the second line. The street name – J.F.K. Blvd. New –includes part of the city name – the New from New York.This happens in any case where the city name consists of more than one word:50 Fifth Ave. New York, NY 10012Becomes:50,Fifth Ave. New,York,NY,10012Instead of what we had before:50,Fifth Ave.,New York,NY,10012Why did this happen? The subpattern [\w .]+ was just greedy. We need to make it lazier so thatthe street name field doesn’t unintentionally swallow part of the city name.TODOTK: (move to laziness chapter?)AnswerThe pattern for the street name is now:([\w .]+?)And the complete pattern is otherwise unchanged:Find ˆ(\d+) ([\w .]+?) ([\w ]+), ([A-Z]{2}) (\d{5})How did one question mark make all the difference?
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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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Match zero-or-more with the star si
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Specific and limited repetition 501
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Specific and limited repetition 52E
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Specific and limited repetition 54C
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Anchors: A way to trim emptinessIn
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Anchors: A way to trim emptiness 58
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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 and 104: Optionality and alternation 96Studi
Page 105 and 106: Optionality and alternation 98You m
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: Lookarounds 114Given this list of c
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
Page 161 and 162: Sorting a police blotter 154Sloppy
Page 163 and 164: Sorting a police blotter 156I used
Page 165 and 166: Converting XML to tab-delimited dat
Page 167 and 168: Converting XML to tab-delimited dat
Page 169 and 170: Cleaning up Microsoft Word HTML(TOD
Page 171 and 172: Cleaning up OCR Text (TODO)Image sc
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Moving forwardThank you for taking
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