Learn how to compare values with the relational operators.
- [Voiceover] The relational operators are used…to compare values in a logical context.…Here's a working copy of relational.pl…from chapter eight of the exercise files.…Relational operators return a value…of true or false.…Now in Perl, anything that is empty or zero…is considered false and anything else…is considered true.…In general, the relational operators will return…the number one for true…and an empty string for false.…These operators are typically used…in conditional context.…
For example, in this if statement here…on line 12, if $a is equal to $b.…Now this is the relational operator…that tests for numeric equality.…It works for numbers, and it does not work for strings.…So testing of $a equals $b, of course $a is 7…and $b is 42.…So if I run this, I will get the result that says false.…And if I change this to say if $a equals $c…which is also 7 like $a and I run it,…then it says true.…
Now some of these relational operators…include the not equal to.…So I can run that, and now it's false again.…Or the less than operator and I run that…
Watch to learn the details of the Perl syntax, from variables, conditionals, loops, and data structures to regular expressions, functions, and references. A quick-start guide is included for experienced developers who want to get up and running with Perl 5 fast, and the entire course is recommended for both new and experienced programmers alike. Later chapters cover file handling and reusing code with Perl modules, plus Perl best coding practices.
- Understanding Perl's general syntax and the anatomy of a Perl script
- Writing statements and expressions
- Creating assignments
- Working with variables and strings
- Using data types effectively
- Defining logical flow with conditionals and loops
- Using special variables
- Using Perl operators
- Performing simple Perl programming tasks with expressions
- Matching data
- Defining and calling functions
- Using references
- Handling files in the file I/O
- Using built-in functions
- Reusing code with modules
- Coding with Perl best practices
Skill Level Intermediate
1. Setting Up
About Perl3m 36s
2. Quick Start
3. Basic Syntax
4. Values and Variables
7. Special Variables
9. Regular Expressions
11. References and Structures
12. File I/O
13. Built-In Functions
15. Best Practices
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