php - 按最受欢迎的数组重新排列数组并使用 PHP 每个实例有 1 个

Question

我想按最流行（最常见）排列数组，然后每个实例只有一个。

例如，

Array ( [0] => cat [1] => dog [2] => bird [3] => dog [4] => dog [5] => cat [6] => turtle )

将会：

Array ( [0] => dog [1] => cat [2] => bird [3] => turtle )

这样做的最佳方法是什么？

Answer 1

结合array_count_values和arsort函数。像这样的东西：

$a = array('cat', 'dog', 'bird', 'dog', 'dog', 'cat', 'turtle');
$a = array_count_values($a); // creating a 'name' => 'occurrence count' array
arsort($a); // sorting them reverse order and maintaining keys
$ordered_animals = array_keys($a); // getting the keys in a separate array

Answer 2

我会用这样的东西：

$reversed = array();
foreach($unsorted as $key => $val){
  if(!isset($reversed[$val])) $reversed[$val] = 0;
  $reversed[$val]++;
}

$sorted = array_keys(asort($reversed));

Answer 3

$items = array( 'cat', 'dog', 'cat', 'hello', 'world', 'dog', 'hello', 'ok' ); // etc

$valueCount = array_count_values( $items );

arsort( $valueCount );

$keys = array_keys( $valueCount );