tailieunhanh - Teach Yourself Perl 5 in 21 days

This book is designed to teach you the Perl programming language in just 21 days. When you finish reading this book, you will have learned why Perl is growing rapidly in popularity: It is powerful enough to perform many useful, sophisticated programming tasks, yet it is easy to learn and previous programming experience is required for you to learn everything you need to know about programming with Perl from this book. In particular, no knowledge of the C programming language is required. If you are familiar with other programming languages, learning Perl will be a snap. The only assumption this book does make is that you. | Teach Yourself Perl 5 in 21 days David Till Table of Contents Introduction Who Should Read This Book Special Features of This Book Programming Examples End-of-Day Q A and Workshop Conventions Used in This Book What You ll Learn in 21 Days Week 1 Week at a Glance Where You re Going Day 1 Getting Started What Is Perl How Do I Find Perl o Where Do I Get Perl o Other Places to Get Perl A Sample Perl Program Running a Perl Program o If Something Goes Wrong The First Line of Your Perl Program How Comments Work o Comments Line 2 Statements Tokens and stdin _ o Statements and Tokens o Tokens and White Space o What the Tokens Do Reading from Standard Input Line 3 Writing to Standard Output o Function Invocations and Arguments Error Messages Interpretive Languages Versus Compiled Languages Summary Q A Workshop o Quiz o Exercises Day 2 Basic Operators and Control Flow Storing in Scalar Variables Assignment o The Definition of a Scalar Variable o Scalar Variable Syntax o Assigning a Value to a Scalar Variable Performing Arithmetic o Example of Miles-to-Kilometers Conversion o The chop Library Function Expressions o Assignments and Expressions Other Perl Operators Introduction to Conditional Statements The if Statement o The Conditional Expression o The Statement Block o Testing for Equality Using o Other Comparison Operators Two-Way Branching Using if and else Multi-Way Branching Using eisif Writing Loops Using the while Statement Nesting Conditional Statements Looping Using the until. Statement Summary Q A Workshop o Quiz o Exercises Day 3 Understanding Scalar Values What Is a Scalar Value Integer Scalar Values o Integer Scalar Value Limitations Floating-Point Scalar Values o Floating-Point Arithmetic and Round-Off Error Using Octal and Hexadecimal Notation o Decimal Notation o Octal Notation o Hexadecimal Notation o Why Bother Character Strings o Using Double-Quoted Strings o Escape Sequences o Single-Quoted Strings Interchangeability of Strings and Numeric Values o Initial