Do php variables need to be defined?

Do php variables need to be defined?

php variables need to be defined. Variables are containers for storing information.

PHP variable rules:

Variables start with a $ symbol, followed by the name of the variable

Variable names must start with a letter or an underscore

Variable names cannot begin with a number

Variable names can only contain alphanumeric characters and underscores (A-z, 0-9, and _)

Variable names are case-sensitive ($y and $Y are two different variables)

Note: PHP variable names are case-sensitive!

Creating PHP variables

PHP does not have a command to create variables.

The variable will be created when it is assigned a value for the first time:

Example

<?php
$txt="Hello world!";
$x=5;
$y=10.5;
?>

After the above statement is executed, the variable txt will save the value Hello world!, and the variable x will save the value 5, the variable y will hold the value 10.5.

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