book

Introducing Regular Expressions

by Michael Fitzgerald

July 2012

Beginner

151 pages

3h 27m

English

O'Reilly Media, Inc.

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Who Should Read This BookWhat You Need to Use This BookConventions Used in This BookUsing Code ExamplesSafari® Books OnlineHow to Contact UsAcknowledgments
Getting Started with RegexpalMatching a North American Phone NumberMatching Digits with a Character ClassUsing a Character ShorthandMatching Any CharacterCapturing Groups and Back ReferencesUsing QuantifiersQuoting LiteralsA Sample of ApplicationsWhat You Learned in Chapter 1Technical Notes
Matching String LiteralsMatching DigitsMatching Non-DigitsMatching Word and Non-Word CharactersMatching WhitespaceMatching Any Character, Once AgainMarking Up the TextUsing sed to Mark Up TextUsing Perl to Mark Up TextWhat You Learned in Chapter 2Technical Notes
The Beginning and End of a LineWord and Non-word BoundariesOther AnchorsQuoting a Group of Characters as LiteralsAdding TagsAdding Tags with sedAdding Tags with PerlWhat You Learned in Chapter 3Technical Notes
AlternationSubpatternsCapturing Groups and BackreferencesNamed GroupsNon-Capturing GroupsAtomic GroupsWhat You Learned in Chapter 4Technical Notes
Negated Character ClassesUnion and DifferencePOSIX Character ClassesWhat You Learned in Chapter 5Technical Notes
Matching a Unicode CharacterUsing vimMatching Characters with Octal NumbersMatching Unicode Character PropertiesMatching Control CharactersWhat You Learned in Chapter 6Technical Notes
Greedy, Lazy, and PossessiveMatching with *, +, and ?Matching a Specific Number of TimesLazy QuantifiersPossessive QuantifiersWhat You Learned in Chapter 7Technical Notes

Positive LookaheadsNegative LookaheadsPositive LookbehindsNegative LookbehindsWhat You Learned in Chapter 8Technical Notes
Matching TagsTransforming Plain Text with sedSubstitution with sedHandling Roman Numerals with sedHandling a Specific Paragraph with sedHandling the Lines of the Poem with sedAppending TagsUsing a Command File with sedTransforming Plain Text with PerlHandling Roman Numerals with PerlHandling a Specific Paragraph with PerlHandling the Lines of the Poem with PerlUsing a File of Commands with PerlWhat You Learned in Chapter 9Technical Notes
Learning MoreNotable Tools, Implementations, and LibrariesPerlPCRERuby (Oniguruma)PythonRE2Matching a North American Phone NumberMatching an Email AddressWhat You Learned in Chapter 10
Regular Expressions in QEDMetacharactersCharacter ShorthandsWhitespaceUnicode Whitespace CharactersControl CharactersCharacter PropertiesScript Names for Character PropertiesPOSIX Character ClassesOptions/ModifiersASCII Code Chart with RegexTechnical Notes

Overview

If you’re a programmer new to regular expressions, this easy-to-follow guide is a great place to start. You’ll learn the fundamentals step-by-step with the help of numerous examples, discovering first-hand how to match, extract, and transform text by matching specific words, characters, and patterns.

Regular expressions are an essential part of a programmer’s toolkit, available in various Unix utlilities as well as programming languages such as Perl, Java, JavaScript, and C#. When you’ve finished this book, you’ll be familiar with the most commonly used syntax in regular expressions, and you’ll understand how using them will save you considerable time.

Discover what regular expressions are and how they work
Learn many of the differences between regular expressions used with command-line tools and in various programming languages
Apply simple methods for finding patterns in text, including digits, letters, Unicode characters, and string literals
Learn how to use zero-width assertions and lookarounds
Work with groups, backreferences, character classes, and quantifiers
Use regular expressions to mark up plain text with HTML5