Data Types Available in PHP

PHP has eight basic data types: four scalar types that hold a single value (integer, float, boolean and string), two compound types that can hold several values (array and object), and two special types (null and resource). To check the type of a value, use var_dump() or gettype().

1. Integer
2. Float/Double
3. Boolean
4. String
5. Array
6. Object
7. Null
8. Resource

Integers: Integers are whole numbers, without a decimal point (…, -2, -1, 0, 1, 2, …)

Floating Point Numbers or Doubles: Floating point numbers (also known as “floats”, “doubles”, or “real numbers”) are decimal or fractional numbers. Example: $a = 1.234; $b = 10.2e3;

Strings: Strings are sequences of characters. The simplest way to specify a string is to enclose it in single quotes (e.g. ‘Hello world!’), however, you can also use double quotes (“Hello world!”). Double quotes also replace variables with their values; see single vs double quotes in PHP.

Booleans: Booleans are like a switch: they have only two possible values, true or false. Example: $show_val = true;

Arrays: An array is a variable that can hold more than one value at a time. The PHP array quick reference shows how to create, sort and search them.

Objects: An object is a data type that not only allows storing data but also information on, how to process that data. An object is a specific instance of a class that serves as templates for objects. Objects are created based on this template via the new keyword.

Null: The special value null means a variable has no value. A variable is null if it has been assigned null, hasn’t been set yet or has been removed with unset().

Resources: A resource is a special variable that holds a reference to something outside PHP, such as an open file from fopen(). Since PHP 8.0, several extensions, cURL among them, return objects instead of resources.

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