Variables are identifiers for some data storage in the programming. We can save some data in memory using a variable, and the variable works as a named identifier of that data storage memory address.
PHP variable naming starts with a dollar sign($) and then there is an identifier(variable name). The identifier/name of the variable should follow certain rules.
WARNING
Variable names in PHP are case-sensitive. So $myVar, $MyVar, and $mYVAR represent 3 different variables.
Function names are not case-sensitive in PHP.
Variable Naming Rules
An identifier/variable name should-
- A non-empty sequence of characters.
- Start with a dollar sign($).
- Can only contain letters(a-z, A-Z, non-English Unicode characters), numbers(0-9), and underscore(_).
- Can not be a reserved keyword(mentioned below).
Variable Naming Convention
We have the following conversion for naming a variable in PHP-
- Should be meaningful and related to the usage of the variable.
- After the dollar sign($) the first character should be lowercase.
- If the variable name contains multiple words then the first letter of each word should be capitalized (except the very first character of the variable name). This is called camel case.
- Do not use underscore(_) in variable names (except the constant naming or there is a specific requirement for underscore).