🧬 PHP Data Types Explained – Strings, Integers, Arrays & More

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🧲 Introduction – Why PHP Data Types Matter

In PHP, everything revolves around variables—and those variables hold data. Understanding PHP data types helps you store, process, and manipulate information accurately and efficiently. PHP is a loosely typed language, which means you don’t need to declare a type explicitly—but you should still understand how types work to avoid bugs and write optimized code.

🎯 In this guide, you’ll learn:

• All major data types in PHP
• Examples of each data type in action
• How PHP handles type juggling
• Best practices and debugging tips

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📦 Categories of PHP Data Types

PHP supports 8 primary data types, grouped into scalar, compound, and special types:

Type Group	Data Types
Scalar	String, Integer, Float, Boolean
Compound	Array, Object
Special	NULL, Resource

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🔤 1. String

A string is a sequence of characters enclosed in quotes.

<?php
$name = "Vaibhav";
echo $name;
?>

✅ Output: Vaibhav

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🔢 2. Integer

An integer is a whole number (positive, negative, or zero).

<?php
$age = 25;
var_dump($age); // int(25)
?>

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🧮 3. Float (Double)

A float (or double) is a number with a decimal point.

<?php
$price = 99.99;
var_dump($price); // float(99.99)
?>

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🔘 4. Boolean

A boolean represents a true or false value.

<?php
$isLoggedIn = true;
var_dump($isLoggedIn); // bool(true)
?>

✅ Booleans are often used in conditional statements.

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📚 5. Array

An array stores multiple values in a single variable.

<?php
$colors = ["red", "green", "blue"];
var_dump($colors);
?>

✅ Arrays can be indexed, associative, or multidimensional.

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🧱 6. Object

An object is an instance of a class containing properties and methods.

<?php
class Car {
    public $model = "Tesla";
}
$car = new Car();
var_dump($car);
?>

✅ Objects are essential for object-oriented programming in PHP.

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🕳️ 7. NULL

A NULL value means “no value assigned”.

<?php
$x = null;
var_dump($x); // NULL
?>

✅ NULL is often used to reset or check uninitialized variables.

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🔌 8. Resource

A resource is a special variable that holds a reference to an external resource — like a database connection or file handle.

<?php
$file = fopen("sample.txt", "r");
var_dump($file); // resource
?>

✅ Mostly used with external APIs, file systems, and database operations.

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🔀 PHP Type Juggling (Automatic Type Conversion)

PHP automatically converts data types when necessary:

<?php
$x = "5";
$y = 10;
echo $x + $y; // Outputs 15 (string converted to integer)
?>

✅ PHP converts the string "5" to integer during the arithmetic operation.

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🚫 Strict Typing (Optional in PHP 7+)

You can enforce strict data types using declare(strict_types=1); at the top of your script:

<?php
declare(strict_types=1);

function add(int $a, int $b): int {
    return $a + $b;
}
echo add(5, 10); // ✅ Works
?>

✅ Helps reduce bugs in larger codebases by enforcing correct types.

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🛠️ Best Practices

Tip	Why It Helps
✅ Use var_dump() for debugging	Reveals both type and value
❌ Don’t rely too much on type juggling	Can cause hard-to-spot bugs
✅ Use strict types in functions	Improves readability and reliability
✅ Validate user input types	Enhances security and prevents misuse

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📌 Summary – Recap & Next Steps

PHP’s data types are the foundation of how values are stored and manipulated. Whether you’re storing text, numbers, or structured data like arrays and objects, knowing the correct data type helps you write robust and secure PHP applications.

🔍 Key Takeaways:

• PHP supports 8 data types: 4 scalar, 2 compound, 2 special
• Type juggling allows flexibility, but strict typing adds safety
• Use var_dump() or gettype() to inspect values during debugging
• Arrays and objects are powerful structures for dynamic data
• Always validate and sanitize external input to prevent errors

⚙️ Real-World Relevance:
From form submissions and user profiles to session data and API responses, PHP data types play a role in every line of your code. Mastering them is essential for full-stack and backend developers.

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❓ Frequently Asked Questions (FAQ)

❓ Do I need to declare data types in PHP?
❌ No. PHP is dynamically typed by default. You can use declare(strict_types=1) for enforcing strict types.

❓ How do I check the type of a variable in PHP?
✅ Use gettype() or var_dump():

var_dump($value); // Shows type and value

❓ What’s the difference between NULL and "" (empty string)?
✅ NULL is no value at all, whereas "" is a value of an empty string.

❓ Can I store multiple data types in one variable?
✅ Not simultaneously. But you can reassign a variable to a different type later:

$val = 10;
$val = "ten"; // Allowed in PHP

❓ What’s a resource in PHP?
✅ A special type used for file handles, DB connections, or external resources like cURL.

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