How can the concept of scope affect PHP functions?

The concept of scope in PHP functions refers to the visibility of variables within the function. If a variable is declared outside of a function, it is considered to be in the global scope and can be accessed from within the function using the global keyword. However, it is generally considered best practice to pass variables as parameters to functions rather than relying on global scope, as this can lead to unexpected behavior and make the code harder to maintain. 

// Incorrect usage of global scope
$globalVar = 10;

function myFunction() {
    global $globalVar;
    echo $globalVar;
}

myFunction(); // Outputs 10

// Correct usage of passing variables as parameters
$localVar = 20;

function myFunction($localVar) {
    echo $localVar;
}

myFunction($localVar); // Outputs 20

Keywords

Scope PHP functions variable global local

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