Data Types & Expressions
PHP supports standard numeric and string data types. Understanding double-quoted variable parsing and debugging tools like var_dump() is crucial.
1 Double Quote Parsing & var_dump() Debugging
Data types in PHP follow standard dynamic definitions:
- Double Quotes vs Single Quotes: Double quotes parse and interpolate variables embedded inside them automatically: `"Hello $name"`. Single-quoted strings treat text strictly as literals: `'Hello $name'` prints the literal string `$name`.
- var_dump(): A powerful debugging function that prints the type and value of an expression, making it the primary tool for debugging variables in PHP.
2 Type Formatting Code
Let's run a program comparing string quotes and inspecting variables using var_dump:
PHP — Data Types
▶ Run Code
<?php
$fruit = "Apple";
$price = 1.99;
$in_stock = true;
// Double quotes parse variables, single quotes do not
echo "Double quotes: $fruit costs $price\n";
echo 'Single quotes: $fruit costs $price\n';
echo "\n";
// Debugging using var_dump()
var_dump($fruit);
var_dump($price);
var_dump($in_stock);
?>3 Code Challenge
Challenge: Declare a null variable. Pass it to `var_dump()` and run the code to observe how PHP represents null values.