array_diff_assoc() returns an array
containing all the values from array1
that are not present in any of the other arguments.
Note that the keys are used in the comparison unlike
array_diff().
In our example above you see the "a" => "green"
pair is present in both arrays and thus it is not in the ouput from the
function. Unlike this, the pair 0 => "red"
is in the ouput because in the second argument "red"
has key which is 1.
Two values from key => value pairs are
considered equal only if (string) $elem1 === (string)
$elem2 . In other words a strict check takes place so
the string representations must be the same.
Note:
Please note that this function only checks one dimension of a n-dimensional
array. Of course you can check deeper dimensions by using, for example,
array_diff_assoc($array1[0], $array2[0]);.