过滤数组，以便删除指定了所有带键的元素

I'm looking for a way to filter array so all elements with key is specified are removed.

Here's an example of what I mean:

$x = array(
    'a', // pass
    'b::a', // pass
    array('a'), // pass
    array('a', 'b'), // pass
    function() { // pass

        return 'a';

    },
    'a' => 'b', // doesn't pass because key is specified
);

After remove_elements_with_key_specified($x)...

array(5) {
    [0]=> string(1) "a"
    [1]=> string(4) "b::a"
    [2]=> array(1) { [0]=> string(1) "a" }
    [3]=> array(2) { [0]=> string(1) "a" [1]=> string(1) "b" }
    [4]=> object(Closure)#1 (0) { }
}

How to do it? Would simple check that key is a string would be the best way?

is_int() would work:

foreach($x as $k=>$v){
    if(!is_int($k)){
        unset($x[$k]);
    }
}

From docs:

<?php
if (is_int(23)) {
    echo "is integer
";
} else {
    echo "is not an integer
";
}
var_dump(is_int(23));
var_dump(is_int("23"));
var_dump(is_int(23.5));
var_dump(is_int(true));
?>

The above example will output:

is integer
bool(true)
bool(false)
bool(false)
bool(false)

All of your elements have an implicit numeric key, so I guess what you wanna do here is something like:

foreach($x as $key => $value) {
    if(!is_numeric($key) {
         unset($x[$key]);
    }
}

That should work.