What could be the reason for a variable not being recognized in PHP code?

The most common reason for a variable not being recognized in PHP code is that it may not have been defined or initialized before being used. To solve this issue, make sure to declare the variable before using it in the code. Additionally, check for any typos in the variable name or scope issues that may prevent the variable from being accessed.

// Variable not recognized issue
$variable = "Hello, World!";

// Correct way to declare and initialize the variable
$variable = "";
$variable = "Hello, World!";

// Ensure proper variable scope
function testFunction() {
    $variable = "Inside function";
    echo $variable;
}

testFunction();