deprecated param in example, missing multidimensional example

[ludrob]

From manual page: https://php.net/function.empty

---

1. Examples contain deprecated params:

var_dump(empty($expected_array_got_string[0.5]));
// Output: Deprecated: Implicit conversion from float 0.5 to int loses precision in php-wasm run script on line 6

Using a float as an array key triggers a deprecation warning because implicit conversion from float to int is no longer fully supported. This example should be revised to use a valid integer key to avoid confusion and comply with current standards.

2. Missing Example for Multidimensional Arrays
   The documentation could benefit from including examples of using empty() with multidimensional arrays, as handling nested keys is a common use case.

Consider the following example:

$multidimensional = [
    'some' => [
        'deep' => [
            'nested' => 'value'
        ]
    ]
];

// Correct usage to avoid warnings:
if (!empty($multidimensional['some']['deep']['nested'])) {
    $someVariable = $multidimensional['some']['deep']['nested'];
}

Most users might unnecessarily write verbose checks due to the fear of triggering warnings:

if (
    !empty($multidimensional) && 
    !empty($multidimensional['some']) && 
    !empty($multidimensional['some']['deep']) && 
    !empty($multidimensional['some']['deep']['nested'])
) {
    $someVariable = $multidimensional['some']['deep']['nested'];
}

To illustrate the safety of empty() with nested arrays, the documentation could include the following example:

var_dump(empty($multidimensional['some-undefined-key'])); // bool(true)
var_dump(empty($multidimensional['some']['deep']['unknown'])); // bool(true)
var_dump(empty($multidimensional['some']['deep']['nested']));  // bool(false)

output

bool(true)  
bool(true)  
bool(false)  

[Girgias]

I agree that more examples would be good, could you provide a PR?

[ludrob]

Sure, see #4394