Check if a variable is defined and not null, so, if the variable is not defined it will return false, if the variable is null it will return false. If the variable is defined, it will return true.

PHP traits are a methodology for code reuse that allows us to group functions, but don't get me wrong, these groupings are not inside the class, you can use the same grouping in different classes.

A constant is a value to which we assign a name, and this value will not change. For example, consider a value of a tax such as VAT. Constants are often used in WordPress configuration as an example. Here's how to define a constant. By convention, the name of the constant is recommended to be in uppercase. A constant distinguishes between uppercase and lowercase letters.

Operators are symbols or keywords used to perform operations in PHP. These are used to manipulate values and variables. Arithmetic Operators Arithmetic operators are used to perform basic mathematical operations in PHP. Operator Name Example Result + Addition $x + $y Sum of $x and $y – Subtraction $x – $y Difference of $x and […]

On PHP the great quantity of variables have a single scope. <?php $variable = "hola mundo"; include "archivo.php"; ?> The variable $varaible is disponible in archive.php except in function. Inside functions variables are in local scope, you can access varaibles inside that function. When we are using functions, we have 3 different situations in where […]