在PHP中以不同的方式合并数组

Question

I have these two arrays:

$array1 = array( '0' => 'apple', '1' => ''   , '2' => 'cucumber' );

$array2 = array( '0' => '',      '1' => 'bmw', '2' => 'chrysler' );

if I do this to merge these arrays:

$result_arr = array_merge($array1, $array2);
print_r( count ( array_filter($result_arr) ) );

the output would be 4.

However, I need to get the number 3. So, when there are two things on the same position (same key) count it only once.

Is it possible to merge/count elements in arrays like that?

Answer 1

One possible way to generate a 'union' of those arrays:

$first  = array( '0' => 'apple', '1' => ''   , '2' => 'cucumber', 3 => '');
$second = array( '0' => '',      '1' => 'bmw', '2' => 'chrysler', 3 => '');

$result = array_map(function($a, $b) {
  return $a ?: $b;
}, $first, $second);
print_r($result); 
/* 
[0] => 'apple'
[1] => 'bmw'
[2] => 'cucumber'
[3] => ''
*/

Demo.

The resulting array will be filled either with non-empty elements from the first array or (if check for non-emptiness fails) with any type of elements from the second array - the latter will serve as a kind of fallback.