Basic PHP Syntax - PHP 8 Tutorial

Summary

This video introduces the basics of PHP, covering key concepts such as PHP file structure, syntax, and output methods. Viewers learn how to create and run PHP files, understand variables, and output text using `echo` and `print`. The video also explains embedding PHP in HTML, handling strings, using comments, and managing PHP variables by value or reference. Best practices, such as avoiding unnecessary closing PHP tags, are discussed. Ideal for beginners, this tutorial helps viewers grasp the essentials of PHP programming to build dynamic web applications.

Takeaways

• 😀 PHP files must end with .php and can contain HTML, CSS, and JavaScript.
• 😀 PHP code is enclosed in opening <?php and closing ?> tags, and these tags are mandatory unless the file contains only PHP code.
• 😀 Avoid using the closing PHP tag if the file only contains PHP code to prevent accidental whitespace or newlines.
• 😀 Use the echo statement to output text or variables to the browser, and remember to always end statements with a semicolon.
• 😀 Unlike Python or JavaScript, PHP requires semicolons to terminate statements, though they are not needed on the last line of a PHP block.
• 😀 PHP can be executed both in the browser (through a server) and the command line (via the `php` command).
• 😀 The `print` statement in PHP is similar to `echo`, but it returns a value (1), allowing it to be used in expressions.
• 😀 Strings with quotes inside them must be escaped with a backslash or enclosed in different types of quotes (single vs. double).
• 😀 Variables in PHP begin with a dollar sign ($), and they cannot start with a number or contain special characters.
• 😀 By default, PHP variables are assigned by value, but you can assign them by reference using the ampersand (&) to link variables.
• 😀 To embed PHP in HTML, use `<?php` to start PHP code and `?>` to end it. There is also a shorthand version `<?='content'?>` for echoing content in a single line.

Q & A

Why must PHP files end with the `.php` extension?

PHP files must end with the `.php` extension so the server knows to process them as PHP code. This ensures that the code inside the PHP tags will be interpreted and executed by the server.

What is the significance of the `<?php ?>` tags in PHP?

The `<?php ?>` tags are used to enclose PHP code, indicating to the server that the code between these tags should be processed as PHP. Without these tags, the server will not interpret the content as PHP.

When is it unnecessary to use the closing PHP tag `?>`?

If a PHP file contains only PHP code, the closing PHP tag `?>` is unnecessary. Omitting it helps prevent accidental whitespace or new lines after the PHP code, which could cause issues like unwanted output in the browser.

What are the differences between `echo` and `print` in PHP?

`echo` and `print` both output data to the screen, but `echo` is marginally faster and doesn't return a value. `print` returns a value of 1, which can be used in expressions, making it more flexible in certain situations.

How can you prevent errors when printing strings with quotes in PHP?

To prevent errors when printing strings with quotes, you can either escape the quote using a backslash (e.g., `Joe's invoice`) or use double quotes for the string (e.g., `"Joe's invoice"`).

What are the rules for naming variables in PHP?

PHP variables must start with a letter or an underscore (`_`). They cannot start with a number or contain special characters like `@` or `-`. Additionally, some reserved words like `this` cannot be used as variable names.

What does it mean to assign variables by value vs. by reference in PHP?

When variables are assigned by value, copying one variable to another does not affect the original. When assigned by reference (using the `&` operator), changes to one variable will affect the other, as they both refer to the same data.

Why is it important to always include semicolons in PHP statements?

Semicolons are used to terminate PHP statements. Omitting them can cause syntax errors. While there are exceptions (e.g., before a closing PHP tag), it's good practice to always include semicolons to avoid errors.

What are the different ways to write comments in PHP?

In PHP, you can write single-line comments using `//` or `#`. Multi-line comments are enclosed in `/* */`. For documenting code, you can use docblocks, which provide structured multi-line comments often used for documentation.

How can PHP code be embedded into HTML?

PHP code can be embedded within HTML by using `<?php ?>` tags. For simple output, the shorthand `<?= ?>` can be used. This allows dynamic content to be generated within static HTML structures.