Regex Quick Syntax Reference : Understanding and Using Regular Expressions

This quick guide to regular expressions is a condensed code and syntax reference for an important programming technique. It demonstrates regex syntax in a well-organized format that can be used as a handy reference, showing you how to execute regexes in many languages, including JavaScript, Python, Java, and C#. The __Regex Quick Syntax Reference__ features short, focused code examples that show you how to use regular expressions to validate user input, split strings, parse input, and match patterns. Utilizing regular expressions to deal with search/replace and filtering data for backend coding is also covered. You won’t find any bloated samples, drawn out history lessons, or witty stories in this book. What you will find is a language reference that is concise and highly accessible. The book is packed with useful information and is a must-have for any programmer. **What You Will Learn** * Formulate an expression * Work with arbitrary char classes, disjunctions, and operator precedence * Execute regular expressions and visualize using finite state machines * Deal with modifiers, including greedy and lazy loops * Handle substring extraction from regex using Perl 6 capture groups, capture substrings, and reuse substrings **Who This Book Is For** If you have dealt with at least one programming language, chances are you know enough to understand regular expressions, and the examples in this book will help you develop proficiency. Contents......Page 3 Why Are Regular Expressions Important?......Page 8 What Are Regular Expressions?......Page 9 Frustrations with Regular Expressions Arise from Lack of Taking Action......Page 11 Regular Expressions Are Imperative......Page 12 The Language Family of Regular Expressions......Page 13 Summar y......Page 15 Formulating an Expression......Page 16 Arbitrary Character Class......Page 20 Alternative Execution......Page 21 Anchored Start and End......Page 22 Modifiers......Page 26 Summary......Page 28 Regular Expressions in JavaScript......Page 29 Other PCRE-Based Regex Environments......Page 40 Regular Expressions Are Finite State Machines......Page 58 Backtracking......Page 60 Deterministic and Nondeterministic Regex Modeling......Page 61 Basic Regex Simplifications......Page 67 Automatically Generating Regex FSMs......Page 68 Summar y......Page 71 Repeat Modifiers......Page 72 Backtracking......Page 73 Match at Least Once......Page 75 Match at Most Once: Optionals......Page 77 Match Any Number of Times......Page 78 Fixed-Range Matching......Page 79 Loop Exactly n Times......Page 82 Greedy Repeat Modifiers......Page 83 Lazy Repeat Modifiers......Page 84 Possessive Repeat Modifiers......Page 87 Summary......Page 89 Character Sets......Page 90 Character Set Ranges......Page 92 Character Set Classes......Page 93 Concatenating Advanced Language Constructs......Page 97 Summar y......Page 98 Substring Extraction from RegEx......Page 99 Defining Capture Groups......Page 100 Perl 6 Capture Groups......Page 101 Retrieval of Captured Substrings......Page 102 Reusing Captured Substrings Within a Regex......Page 108 Capture Groups and Performance......Page 110 Summary......Page 112 Lookahead......Page 113 Lookbehind......Page 116 Summary......Page 117 Maintaining Regular Expressions......Page 118 Extended Mode......Page 119 Regex Subroutines......Page 121 Named Capture Groups......Page 125 Case Study: XRegExp Library for JavaScript......Page 128 Summary......Page 131 Optimizing Regular Expressions......Page 133 Making Character Classes More Specific......Page 134 Repeating Character Class Loops......Page 136 Use Possessive Repeat Modifiers Whenever Possible......Page 137 Use Atomic Groups......Page 138 Optimization Techniques Limit Nondeterministic Execution......Page 140 Summary......Page 141 Parsing HTML Tags......Page 142 Processing the Query String of a URL......Page 145 This is not the End, but the Beginning......Page 147 “What If I Want to Learn More?”......Page 149 Keep in Touch......Page 150 Index......Page 151 This quick guide to regular expressions is a condensed code and syntax reference for an important programming technique. It demonstrates regex syntax in a well-organized format that can be used as a handy reference, showing you how to execute regexes in many languages, including JavaScript, Python, Java, and C#. The Regex Quick Syntax Reference features short, focused code examples that show you how to use regular expressions to validate user input, split strings, parse input, and match patterns. Utilizing regular expressions to deal with search/replace and filtering data for backend coding is also covered. You won't find any bloated samples, drawn out history lessons, or witty stories in this book. What you will find is a language reference that is concise and highly accessible. The book is packed with useful information and is a must-have for any programmer. What You Will Learn Formulate an expression Work with arbitrary char classes, disjunctions, and operator precedence Execute regular expressions and visualize using finite state machines Deal with modifiers, including greedy and lazy loops Handle substring extraction from regex using Perl 6 capture groups, capture substrings, and reuse substrings Who This Book Is For: If you have dealt with at least one programming language, chances are you know enough to understand regular expressions, and the examples in this book will help you develop proficiency.--Provided by publisher "This quick guide to regular expressions is a condensed code and syntax reference for an important programming technique. It demonstrates regex syntax in a well-organized format that can be used as a handy reference showing you how to execute regexes in many languages, including JavaScript, Python, Java, and C#. The Regex Quick Syntax Reference features short, focused code examples that show you how to use regular expressions to validate user input, split strings, parse input, and match patterns. Utilizing regular expressions to deal with search/replace and filtering data for backend coding is also covered. You won't find any bloated samples, drawn out history lessons, or witty stories in this book. What you will find is a language reference that is concise and highly accessible. The book is packed with useful information and is a must-have for any programmer. You will: formulate an expression; work with arbitrary char classes, disjunctions, and operator precedence; execute regular expressions and visualize using finite state machines; use greedy, lazy, and possessive repeat modifiers for looping in regular expressions; handle substring extraction from regex using Perl 6 capture groups, capture substrings, and reuse substrings."--Page 4 of cover This quick guide to regular expressions is a condensed code and syntax reference for an important programming technique. Using JavaScript and Perl 6 code, it demonstrates regex syntax in a well-organized format that can be used as a handy reference. The Regex Quick Syntax Reference features short, focused code examples that show you how to use regular expressions to validate user input, split strings, parse input, and match patterns. Utilizing regular expressions to deal with search/replace and filtering data for backend coding is also covered. You won't find any bloated samples, drawn out history lessons, or witty stories in this book. What you will find is a language reference that is concise and highly accessible. The book is packed with useful information and is a must-have for any programmer. You will: Formulate an expression Work with arbitrary char classes, disjunctions, and operator precedence Execute regular expressions and visualize using finite state machines Deal with modifiers, including greedy and lazy loops Handle substring extraction from regex using Perl 6 capture groups, capture substrings, and reuse substrings