PHP data types are used to hold different types of data or values. PHP supports 8 primitive data types that can be categorized further in 3 types:
- Scalar Types [predefined]
- Compound Types [user-defined]
- Special Types
PHP Data Types: Scalar Types
It holds only single value. There are 4 scalar data types in PHP.
- boolean
- integer
- float
- string
PHP Data Types: Compound Types
It can hold multiple values. There are 2 compound data types in PHP.
- array
- object
PHP Data Types: Special Types
There are 2 special data types in PHP.
- resource
- NULL
PHP Boolean
Booleans are the simplest data type works like switch. It holds only two values: TRUE [1] or FALSE [0]. It is often used with conditional statements. If the condition is correct, it returns TRUE otherwise FALSE.
Example:
Output:
PHP Integer
Integer means numeric data with a negative or positive sign. It holds only whole numbers, i.e., numbers without fractional part or decimal points.
Rules for integer:
- An integer can be either positive or negative.
- An integer must not contain decimal point.
- Integer can be decimal [base 10], octal [base 8], or hexadecimal [base 16].
- The range of an integer must be lie between 2,147,483,648 and 2,147,483,647 i.e., -2^31 to 2^31.
Example:
Output:
Decimal number: 34 Octal number: 163 HexaDecimal number: 69
PHP Float
A floating-point number is a number with a decimal point. Unlike integer, it can hold numbers with a fractional or decimal point, including a negative or positive sign.
Example:
Output:
Addition of floating numbers: 73.812
PHP String
A string is a non-numeric data type. It holds letters or any alphabets, numbers, and even special characters.
String values must be enclosed either within single quotes or in double quotes. But both are treated differently. To clarify this, see the example below:
Example:
Output:
Hello Javatpoint Hello $company
PHP Array
An array is a compound data type. It can store multiple values of same data type in a single variable.
Example:
Output:
array[3] { [0]=> string[13] "Royal Enfield" [1]=> string[6] "Yamaha" [2]=> string[3] "KTM" }
Array Element1: Royal Enfield
Array Element2: Yamaha
Array Element3: KTM
You will learn more about array in later chapters of this tutorial.
PHP object
Objects are the instances of user-defined classes that can store both values and functions. They must be explicitly declared.
Example:
Output:
Bike Model: Royal Enfield
This is an advanced topic of PHP, which we will discuss later in detail.
PHP Resource
Resources are not the exact data type in PHP. Basically, these are used to store some function calls or references to external PHP resources. For example - a database call. It is an external resource.
This is an advanced topic of PHP, so we will discuss it later in detail with examples.
PHP Null
Null is a special data type that has only one value: NULL. There is a convention of writing it in capital letters as it is case sensitive.
The special type of data type NULL defined a variable with no value.
Example:
Output:
In this tutorial you will learn about the data types available in PHP.
Data Types in PHP
The values assigned to a PHP variable may be of different data types including simple string and numeric types to more complex data types like arrays and objects.
PHP supports total eight primitive data types: Integer, Floating point number or Float, String, Booleans, Array, Object, resource and NULL. These data types are used to construct variables. Now let's discuss each one of them in detail.
PHP Integers
Integers are whole numbers, without a decimal point [..., -2, -1, 0, 1, 2, ...]. Integers can be specified in decimal [base 10], hexadecimal [base 16 - prefixed with 0x] or octal [base 8 - prefixed with 0] notation, optionally preceded by a sign [- or +].
Note: Since PHP 5.4+ you can also specify integers in binary [base 2] notation. To use binary notation precede the
number with 0b [e.g. $var = 0b11111111;].
PHP Strings
Strings are sequences of characters, where every character is the same as a byte.
A string can hold letters, numbers, and special characters and it can be as large as up to 2GB [2147483647 bytes maximum]. 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!"].
You will learn more about strings in PHP Strings tutorial.
PHP Floating Point Numbers or Doubles
Floating point numbers [also known as "floats", "doubles", or "real numbers"] are decimal or fractional numbers, like demonstrated in the example below.
PHP Booleans
Booleans are like a switch it has only two possible values either 1 [true] or 0
[false].
PHP Arrays
An array is a variable that can hold more than one value at a time. It is useful to aggregate a series of related items together, for example a set of country or city names.
An array is formally defined as an indexed collection of data values. Each index [also known as the key] of an array is unique and references a corresponding value.
You will learn more about arrays in PHP Array tutorial.
PHP 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 which serve as templates for objects. Objects are created based on this template via the new keyword.
Every object has properties and methods corresponding to those of its parent class. Every object instance is completely independent, with its own properties and methods, and can thus be manipulated independently of other objects of the same class.
Here's a simple example of a class definition followed by the object creation.
Tip: The data elements stored within an object are referred to as its properties and the information, or code which describing how to process the data is called the methods of the object.
PHP NULL
The special NULL value is used to represent empty variables in PHP. A variable of type NULL is a variable without any data. NULL is the only possible value of type null.
When a variable is created without a value in PHP like $var; it is automatically assigned a value of null. Many novice PHP developers mistakenly considered both $var1 = NULL; and $var2 = ""; are same, but this is not true. Both variables are different — the $var1 has null value
while $var2 indicates no value assigned to it.
PHP Resources
A resource is a special variable, holding a reference to an external resource.
Resource variables typically hold special handlers to opened files and database connections.