How can I prevent PHP from interpreting the string ‘Function’ as a function?

Solution 1:

Yes, you can use a variable named $Function, but you need the dollar sign. Without it, PHP interprets Function as a reserved word or constant.

if (isset($Function)) {
    if ($Function == 'A') {
        $functionID = '4';
    } elseif ($Function == 'B') {
        $functionID = '11';
    }  
} else {
    $functionID = 0;
}

Key Points:

Function vs $Function

Function → reserved word in PHP.

$Function → a variable.

Other variations:

“Function” → string.

Some_Function → constant (if defined).

Some_Function() → function call.

✅ Always use the dollar sign when referring to a variable to avoid syntax errors.

Solution 2:

If your data is stored in an array, you need to access the element by its key instead of using a standalone variable.

// Suppose your array is:
$arr = [
    'Function' => 'A',
    'OtherField' => 123
];

// Check the value of the 'Function' key
if ($arr['Function'] == 'A') {
    // ...your action code here
}

Key Points:

$arr[‘Function’] accesses the value associated with the ‘Function’ key.

$Function (a variable) is not the same as $arr[‘Function’].

Always use the correct syntax when working with arrays to avoid undefined variable errors.

✅ This ensures you are actually checking the value stored inside the array, not a separate variable.