What is Variable in PHP
Variable are “containers” for storing information.
All variable in PHP start with a $ (dollar) sign followed by the name of the variable.
A valid variable name starts with a letters, numbers, or underscore (_), followed by any number of letters, number of letters, number, or underscores.
If a variable name is more than one word, it can be separated with underscore.
Syntax of declaring a variable in PHP is given below:
PHP has a total of eight data types which we use to construct our variables −
- Integers − are whole numbers, without a decimal point, like 4195.
- Doubles − are floating-point numbers, like 3.14159 or 49.1.
- Booleans − have only two possible values either true or false.
- NULL − is a special type that only has one value: NULL.
- Strings − are sequences of characters, like ‘PHP supports string operations.’
- Arrays − are named and indexed collections of other values.
- Objects − are instances of programmer-defined classes, which can package up both other kinds of values and functions that are specific to the class.
- Resources − are special variables that hold references to resources external to PHP (such as database connections).
The first five are simple types, and the next two (arrays and objects) are compound – the compound types can package up other arbitrary values of arbitrary type, whereas the simple types cannot.
PHP Variable: Declaring string, integer and float
Let’s see the example to store string, integer and float values in PHP variables.
PHP Variable: Sum of two variables