Copyright © 2003 ProsoftTraining. All rights reserved. Perl Fundamentals

Copyright © 2003 ProsoftTraining. All rights reserved.

PerlFundamentals


Lesson 1:Introduction to Perl

Objectives

• Describe the benefits of Perl• Explain the role of the Perl interpreter• Identify the characteristics of Perl’s basic

syntax• Describe the use of the print function• Create and execute a simple Perl script• Define scalar variables• Use scalar variables to manipulate numerical

and string data• Use expression operators• Retrieve data from STDIN

Practical Extractingand Reporting Language

• Why use Perl?– Innate flexibility– Simple syntax– Relaxed compiler instructions– Free

Getting Startedwith Perl

• The shebang line• Creating a simple Perl script

Scalar andNumerical Variables

• Assignment• Expressions

String Variables

• Second type of scalar variable• The print function

RetrievingData from STDIN

• The chomp() function

Summary

Describe the benefits of Perl Explain the role of the Perl interpreter Identify the characteristics of Perl’s basic

syntax Describe the use of the print function Create and execute a simple Perl script Define scalar variables Use scalar variables to manipulate numerical

and string data Use expression operators Retrieve data from STDIN


Lesson 2:Flow Control

in Perl

Objectives

• Evaluate Boolean expressions• Construct an if statement• Discuss else and elsif branches• Construct a while loop, a do {} while loop,

and a for loop• Use loop-control commands• Describe the I/O redirection paradigm

BooleanExpressions in Perl

• Numeric Boolean expressions• String Boolean expressions• Logical operators

The ifStatement

• The else branch• The elsif branch

The whileStatement

• Second type of control structure• Defines a block of code that will be executed

repeatedly as long as some Boolean expression evaluates as true

The do { } whileStatement

• Similar to the while loop except that the condition is not evaluated until the code block has already been executed once

The forStatement

• Includes three expressions separated by semicolons

• Incorporates facilities for initializing a counter and incrementing it on each turn through the code block

Loop-ControlCommands

• last• next• redo

I/O Redirection

• Many Perl scripts use I/O redirection in place of more complicated file-handling subroutines

Summary

Evaluate Boolean expressions Construct an if statement Discuss else and elsif branches Construct a while loop, a do {} while loop,

and a for loop Use loop-control commands Describe the I/O redirection paradigm


Lesson 3:Regular

Expressions in Perl

Objectives

• Define regular expressions• Perform pattern matching• Define and use metacharacters, quantifiers

and assertions• Explain character classes• Perform substitution• Use the binding operator

Introduction toRegular Expressions

• Pattern binding operators• Escape sequences and metacharacters

Character Classes

• Indicate a list of characters that one element in a string will match

Pattern Matchingand Substitution

• Back references

Summary

Define regular expressions Perform pattern matching Define and use metacharacters, quantifiers

and assertions Explain character classes Perform substitution Use the binding operator


Lesson 4:Arrays in Perl

Objectives

• Describe the purpose of arrays• Define arrays using lists• Access array elements• Use the sort function to sort an array

alphabetically• Use a foreach loop to traverse an array• Use the push, pop, shift, unshift, split and join functions

Introductionto Perl Arrays

• Initializing arrays• Accessing array elements

The sortFunction

• Accepts an array as an argument, alphabetizes the elements within the array, and returns the resultant array

The foreachStatement

• A special control structure designed to iterate through an array or list

The push andpop Functions

• The push function adds values to the top of a stack

• The pop function removes values from a stack

The shift andunshift Functions

• The unshift function adds a value to the front of an array and shifts the rest of the array by one

• The shift function removes values from an array

• Using an array as a queue

The split andjoin Functions

• The split function accepts two arguments, a regular expression and a string

• The join function accepts a list of values and combines them into a single string

Summary

Describe the purpose of arrays Define arrays using lists Access array elements Use the sort function to sort an array

alphabetically Use a foreach loop to traverse an array Use the push, pop, shift, unshift, split and join functions


Lesson 5:Hashes in Perl

Objectives

• Describe the purpose of hashes• Define hashes using lists• Access hash elements• Use the delete, keys, values, each, and reverse functions

Introductionto Perl Hashes

• Hashes are collections of scalar values that can be accessed individually

• Hash elements are accessed using an arbitrary scalar value, called a key

• Also known as associative arrays

Adding andDeleting Hash Elements

• The delete function• The keys function• The values function• The each function• The reverse function

Summary

Describe the purpose of hashes Define hashes using lists Access hash elements Use the delete, keys, values, each, and reverse functions


Lesson 6:Subroutines

in Perl

Objectives

• Define and use a subroutine• Call subroutines directly and indirectly• Pass values to a subroutine• Pass references to a subroutine• Explain variable scope• Return a value from a subroutine

Introductionto Perl Subroutines

• Defining subroutines• Calling subroutines• Passing arguments• Returning values• The sort function and subroutines

Variable Scope

• Variables can be created within subroutines that are private (specific) to just that subroutine using the my operator– The my operator takes a scalar, array, or

hash name and instantiates local versions inside a subroutine

References

• Creating and referencing anonymous arrays• Creating and referencing anonymous hashes• Passing references to subroutines

Summary

Define and use a subroutine Call subroutines directly and indirectly Pass values to a subroutine Pass references to a subroutine Explain variable scope Return a value from a subroutine


Lesson 7:File Input

and Output

Objectives

• Define and use filehandles• Obtain a filehandle using the open function• Output data to a file• Close a file using the close function• Open a file for reading• Use the stat and lstat functions to obtain

information about a file

Perl File Input and Output

• What is a filehandle?• The open function• Outputting data to a file• Opening files for reading• Other file-related functions• Determining information about files• The stat and lstat functions

Summary

Define and use filehandles Obtain a filehandle using the open function Output data to a file Close a file using the close function Open a file for reading Use the stat and lstat functions to obtain

information about a file


Lesson 8:Environment Variables

and Command Line Arguments

Objectives

• Access and use environment variables• Use command line arguments• Define options when handling command line

arguments

Environment Variables

• What are environment variables?– Shells

Command LineArguments

• Arguments entered at the command line can be used in Perl programs

Summary

Access and use environment variables Use command line arguments Define options when handling command line

arguments


Lesson 9:Packages and Modules in Perl

Objectives

• Describe the purpose of packages• Use the package keyword• Use BEGIN and END blocks• Describe the purpose of modules• Create a module to facilitate code reuse• Incorporate a module into your Perl scripts

using the use and require statements• Use the Exporter module

Using Packages in Perl

• Namespace• The package keyword• Package symbol tables

BEGIN and END Blocks

• Special blocks of code defined within a package

UsingModules in Perl

• Specially designed Perl scripts that package functionality for reuse by other Perl scripts

The use andrequire Statements

• The require statement takes a single argument (the name of the module to include)

• The use statement adds symbols directly to the including package’s symbol table

Summary

Describe the purpose of packages Use the package keyword Use BEGIN and END blocks Describe the purpose of modules Create a module to facilitate code reuse Incorporate a module into your Perl scripts

using the use and require statements Use the Exporter module


Lesson 10:Object-Oriented Perl

Objectives

• Describe the purpose of objects• Define objects for use in your Perl scripts• Access object data• Define and use object methods• Use inheritance to expand the functionality of

a class

Introduction toObject-Oriented Perl

• Creating objects• Object data• Object methods

Inheritance

• @ISA array• Destructor methods

Summary

Describe the purpose of objects Define objects for use in your Perl scripts Access object data Define and use object methods Use inheritance to expand the functionality of

a class


Lesson 11:Database

Connectivity and Perl

Objectives

• Define database programming• Explain the benefits of using a database• Define and use the DBI, the DBD, and SQL• Open a database connection• Query a database• Return records from a database• Insert records into a database• Close a connection to a database

Introduction toDatabase Connectivity

• Database programming• Database Interface Module• Database Driver Module

Interactingwith Databases

1. Connect to the database

2. Query the database

3. Display the results

4. Close the connection

Connectingto Databases

• The connect method

StructuredQuery Language

• Data Definition Language– CREATE– DROP

• Data Query Language• Data Manipulation Language

– INSERT– DELETE– UPDATE

QuotingOperators

• Perl includes quoting operators that can be used instead of single or double quotation marks

Summary

Define database programming Explain the benefits of using a database Define and use the DBI, the DBD, and SQL Open a database connection Query a database Return records from a database Insert records into a database Close a connection to a database


Lesson 12:Debugging

Perl Programs

Objectives

• Debug Perl programs• Use the –w switch• Use the strict module• Issue commands to the Perl debugger• Trace the execution of a Perl script• Design Perl scripts to minimize bugs

Introduction toDebugging Perl Scripts

• Using the print command• Using the –w switch• Using the strict module

The PerlDebugger

• Traps and fixes errors in a Perl script• An interactive Perl environment wherein the

user is prompted for debugger commands

WritingBug-Free Perl Code

• Preventing errors• Common Perl errors

Summary

Debug Perl programs Use the –w switch Use the strict module Issue commands to the Perl debugger Trace the execution of a Perl script Design Perl scripts to minimize bugs

Perl Fundamentals

Introduction to Perl Flow Control in Perl Regular Expressions in Perl Arrays in Perl Hashes in Perl Subroutines in Perl File Input and Output in Perl

PerlFundamentals

Environment Variables and Command Line Arguments

Packages and Modules in Perl Object-Oriented Perl Database Connectivity and Perl Debugging Perl Programs

Documents

Copyright © 2003 ProsoftTraining. All rights reserved. Perl Fundamentals