In this movie, you'll practice using alternate quote operators.
- [Voiceover] Perl provides a number of alternate quote operators. These are particularly useful in cases where normal quotes may not work easily. And you notice I run this, it says "Hello, World" in the output. Now let's say that I didn't wanna use the quote marks for whatever reason, and we'll talk about reasons in a minute. Instead, I could use the letter Q and a pair of matching characters. So I can use an opening parenthesis here and a closing parenthesis here, instead of the closing quote mark, and save and run, and you'll notice that the output is exactly the same.
So what are some reasons that I might wanna do this? Perhaps I wanted to use regular quote marks inside of the string, and so if I do that, now our output says "Hello, World" with the quotes. But if I were to try that with the regular quote marks, I would get an error about a Bareword. Missing operator before World. So that doesn't work. So instead, I can use these alternate quote marks like this, and the output is what I expect.
The script now works. So with the single Q, it works just like a single quote mark, so it doesn't do any interpolation. So if I put in a new line here and run this, you notice we get that \n right there in the output. It's not interpolating the new line as we would with double quote marks. While there is an alternate quote operator for the double quote marks also, and it's just a double Q with the delimiters. And when I run that, now we get the new line.
It's interpolating that \n as a new line, just as it would with double quote marks. So these string quote operators are useful for circumstances where normal quotes might be inconvenient. I'm gonna just clean this up a little bit, so we can make some more examples. It's notable that other delimiters will work with the quote operators, so instead of the parentheses, if I wanted to, I could use curly braces, because maybe I've got parentheses in my string, right? And run that, and it works as we expected.
We can use square brackets, like that. And that works. Or we can even use vertical bars, and you actually see this quite a bit in people's code. And I go ahead and run that, and that works too. There's also a quote words operator for making convenient lists of words. And so that looks like this.
And now I can say foreach, my array, and when I run this, you notice I get the list of words there in my output. And so this is called the quote words operator. Most of these alternate quote operators are unique to Perl. You won't see this in a lot of languages, but it makes this process very simple. It's not uncommon to need just a list of strings, a list of single-word strings, in an array, and this is just a really easy way to do that.
And just like with the other alternate quote operators, you can use whatever delimiters you want, and they will work. Now there are some rules about the delimiters, but for the most part, Perl simply tries to do what you mean. So they'll generally work as expected, unless you try to do something really tricky. These alternate quote operators are very convenient, and they're very common in Perl. You'll see a lot more examples as we continue this course.
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
Programming Foundations: Refactoring Codewith Simon Allardice1h 44m 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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