Get difference between two multidimensional arrays by comparing rows [duplicate]

Question

I have two nested arrays and need to find the difference between the reference array and the data array. I am using array_dif_assoc function, and am unable to get the right difference, I am not sure why I am unable to get it. Could somebody help me out if I am doing some mistake or if I have to do it recursively;

$allCoursesAvailable = array(array('id'=>0,'name'=>'Select-One'), array('id'=>1,'name'=>'course1'),array('id'=>1,'name'=>'course2'),array('id'=>3,'name'=>'course3'));

$allCoursesforUser = array(array('id'=>0,'name'=>'Select-One'), array('id'=>1,'name'=>'course1'),array('id'=>4,'name'=>'course4'),array('id'=>5,'name'=>'course5'),array('id'=>6,'name'=>'course4'));

echo '<pre>';print_r(array_diff_assoc($allCoursesAvailable,$allCoursesforUser));

I am getting an empty array with this. When I use array_diff_assoc(), I should have got the arrays carrying course2 and course3, as they are not part of the 2nd array.

Am I missing some logic on the PHP end?

Answer 1

You should not use _assoc but the normal array_diff or array_intersect, because otherwise it will compare the ordering of the outer array and not just the content.

Also array_diff doesn't really work with subarrays, and you'd need a workaround:

print_r(
  array_map("unserialize",
    array_diff(
      array_map("serialize", $allCoursesAvailable),
      array_map("serialize", $allCoursesforUser)
    )
  )
);

Which would give you:

[2] => Array
    (
        [id] => 1
        [name] => course2
    )

[3] => Array
    (
        [id] => 3
        [name] => course3
    )

Not sure if that is what you wanted. And doing it manually might be advisable still.