Array_udiff对象数组使得数组包含的对象只存在一个特定方法的实例

问题描述：

I need to transorm an array of objects so that for instance, the array will only contain 1 object where the object property 'bar' = b.

So I'd like to turn:

   Array ( [0] => stdClass Object ( 
    [id] = 1
    [foo] => 'a' 
    [bar] => 'b' )

    [1] => stdClass Object ( 
    [id] => 2
    [foo] => 'a' 
    [bar] => 'c' )

    [2] => stdClass Object ( 
    [id] => 3
    [foo] => 'y' 
    [bar] => 'b' )  )

into:

     Array ( [0] => stdClass Object ( 
    [id] = 1
    [foo] => 'a' 
    [bar] => 'b' )

    [1] => stdClass Object ( 
    [id] => 2
    [foo] => 'a' 
    [bar] => 'c' )

However, I need this to work on a larger scale, so I am stumped on how to combine array_filter, array_udiff and array_slice to get what I want. I was thinking that array_filter would get me all the keys where 'foo' = 'b'. Then I could take this array and array_udiff it against the original to get the items where 'foo'=! 'b'. Then I could slice the matches from the array_filter to get a single-key array... and merge that back with the array_udiff difference.

$matches = array_filter($array, "bar_filter");

$remainder = array_udiff($array, $matches, 'compare_objects');

$single =  array_slice( $matches, 0, 1);

$result = array_merge($single, $remainder);

function foobar_filter($obj) {
    if ( $obj->bar == 'b' ) {
        return true;
    } else {
        return false;
    }
}

function compare_objects($obj_a, $obj_b) {
  return $obj_a->id = $obj_b->id;
}

My compare_objects function is off for sure, but I don't know what to put there. Would it be better to just run a second array_filter to get the non-matching items? I need to split the array into keys where 'bar'='b' and where 'bar'!='b' and merge it back together with only 1 object where 'bar'='b'

答

Ok, so for clarity, I'll do it in one loop.

$matches = array();
$remainder = array();

// $index if you need to maintain index=>object relation
foreach($array as $index => $object) {
  if($object->bar == "b")
    $matches[] = $object;
  else
    $remainder[] = $object;
}

-- for loop

for($index=0,$count=count($array);$index<$count;$index++) {
  if($object->bar == "b")
    $matches[] = $array[$index];
  else
    $remainder[] = $array[$index];
}

then you would like to merge the result with the first index in $matches

$result = array_merge(array($matches[0]),$remainder);

If this is the case, then you just need to change the compare object body, which should do the trick in filtering the remaining objects out

return $obj_a->id == $obj_b->id ? 0 : 1;

Array_udiff对象数组使得数组包含的对象只存在一个特定方法的实例

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