Variable Declaration in PHP
Variables in PHP are declared by preceding the variable name with the dollar sign ( $ ). Next, we will see some rules to keep in mind for variable naming.
Naming Rules
Case-Sensitivity: All variable names are case-sensitive, which means that the variable $num is different from the variable $Num.
Label-Rule: Variable names must start with a letter or an underscore ( _ ), followed by a combination of letters, numbers, or underscores. When it comes to letters in this case, it includes not only a-z and A-Z but also bytes from 128 to 255 (0x80-0xff).
Declaration and Initialization
In PHP, variables are always declared and initialized in one statement. It is also not necessary to indicate the data type that the variable will contain. Let's see how to declare and initialize different types of variables.
// this variable will be of type string
$name = 'Bob';
// this variable will be of type integer
$age = 78;
// this variable will be of type double
$height = 168.7;
Now take a look at these variable declarations, some are correct and some are incorrect. In each case, the reason is explained with a PHP comment before the declaration.
// invalid, starts with a number
$4site = 'not yet';
// valid; starts with underscore
$_4site = 'not yet';
// valid; 'ä' is an extended ASCII character (ASCII 228)
$täyte = 'mansikka';
That's all for our post on declaration and initialization. There are many other peculiarities regarding variable assignment that we will see as our PHP series progresses. See you soon!