All data in PHP variables fall into one of eight basic categories, known as data types.
A variable's data type determines what operations can be carried out on the variable's data, as well as the amount of memory needed to hold the data.
PHP supports four scalar data types.
Scalar data means data that contains only a single value.
Here's a list of them, including examples:
| Scalar Data Type | Description | Example |
|---|---|---|
| Integer | A whole number | 15 |
| Float | A floating - point number | 8.23 |
| String | A series of characters | "Hello, world!" |
| Boolean | Represents either true or false | true |
PHP supports two compound types.
Compound data is data that can contain more than one value.
The following table describes PHP's compound types:
| Compound Data Type | Description |
|---|---|
| Array | An ordered map (contains names or numbers mapped to values) |
| Object | A type that may contain properties and methods |
PHP supports two special data types
| Special Data Type | Description |
|---|---|
| Resource | Contains a reference to an external resource, such as a file or database |
| Null | May only contain null as a value |