PHP Variables

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What is a Variable in PHP

Variables in PHP are used to store data such as strings of text, numbers, and more. Variable values can be modified during the execution of a script. Here are some important points about variables:

In PHP, a variable does not need to be explicitly declared before assigning a value to it. PHP automatically determines the data type based on the assigned value.
Once a variable is declared, it can be used multiple times throughout the code.
The assignment operator (=) is used to assign a value to a variable.

In PHP, variables are declared as follows: $var_name = value;

Example

Run this code »

<?php
// Declaring variables
$txt = "Hello World!";
$number = 10;

// Displaying variables value
echo $txt;  // Output: Hello World!
echo $number; // Output: 10
?>

In the example above, we created two variables: the first assigned a string value and the second assigned a number. Later, we displayed the variable values in the browser using the echo statement. The PHP echo statement is commonly used to output data to the browser. We will delve deeper into this in upcoming chapters.

Naming Conventions for PHP Variables

These are the rules for naming PHP variables:

All variables in PHP begin with a $ sign, followed by the variable name.
A variable name must start with a letter or the underscore character _.
A variable name cannot start with a number.
A variable name in PHP may only contain alphanumeric characters and underscores (A-z, 0-9, and _).
A variable name cannot contain spaces.

Note: Variable names in PHP are case-sensitive, meaning $x and $X are considered as two distinct variables. Therefore, ensure careful consideration when defining variable names.

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