Discover how local scoping works in Perl.
- [Voiceover] If you've been following the course…in sequence, you've probably noticed…that we have been declaring variables…with the my keyword.…This provides lexical scoping,…where the variable is local to a block of code.…Here's a working copy of function.pl…from Chapter 10 of the Exercise Files.…A my variable has scope…that's local to a block of code,…so if I declare a variable here,…the block of code is actually the file.…It's important to know that in Perl,…a block is either enclosed in curly braces…like this function body, or a file,…so if we declare a my variable outside of a function,…its scope is the whole file.…
So I'm gonna say my $x = 42,…and inside the function, I'll say,…"x is $x"…and when I run this, you see it says x is 42,…which is what we would expect.…Now, if we declare a my variable inside the function…with exactly the same name,…now when I run it, you notice that the value…is taken from the x that's declared inside the function…and not the one that's declared outside the function.…
That's because the my keyword creates a variable…
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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