如何计算多维数组中的所有值?

How to count all values in a multidimensional array?

我已经尝试过许多类似问题的解决方案,但它们似乎都为我提供了每个数组的计数。所以我有以下数组:

Array
(
    [1] => Array
        (
            [0] => 1
            [1] => 12
            [2] => 2
        )

    [2] => Array
        (
            [0] => 1
            [1] => 13
            [2] => 3
        )

    [3] => Array
        (
            [0] => 1
            [1] => 12
            [2] => 2
        )

    [4] => Array
        (
            [0] => 1
        )

    [5] => Array
        (
            [0] => 1
        )

)

我正在尝试计算所有数组中的重复项。所以输出应该显示:

Five 1's
Two 12's
One 13
Two 2's

目前我正在尝试:

foreach($data as $key => $row) {
    print_r(array_count_values($row));
}

输出每个单独数组的计数

Array
(
    [1] => 1
    [12] => 1
    [2] => 1
)
Array
(
    [1] => 1
    [13] => 1
    [3] => 1
)
Array
(
    [1] => 1
    [12] => 1
    [2] => 1
)
Array
(
    [1] => 1
)
Array
(
    [1] => 1
)

我也试过这个:

foreach ($data as $key => $row) {
    $counts = array_count_values(array_column($data, $key));
    var_dump($counts);
}

这似乎遗漏了很多信息,比如 1 的计数

array(2) {
  [12]=>
  int(2)
  [13]=>
  int(1)
}
array(2) {
  [2]=>
  int(2)
  [3]=>
  int(1)
}
array(0) {
}
array(0) {
}
array(0) {
}

请注意,初始数组键并不总是连续的,因为这代表行号。所以这个数组可能包含第 1、2、5、6、7 等行

我将如何计算所有重复项?

通过使用累加器数组并迭代所有元素,您可以很容易地做到这一点:

$result = [];
foreach ($data as $row) {
    foreach($row as $value) {
        $result[$value] = isset($result[$value]) ? $result[$value] + 1 : 1;
    }
}
var_dump($result);

由于您的数组没有展平,除非您想调用合并函数,否则您将需要访问每个值并递增。

代码:(Demo)

$array = [
    1 => [1, 12, 2],
    2 => [1, 13, 3],
    3 => [1, 12, 2],
    4 => [1],
    5 => [1]
];

//           make the generated value available outside of function scope
//           \-------------------------------v--------------------------/
array_walk_recursive($array, function($v)use(&$output) {  // visit each leafnode
    if (isset($output[$v])) {  // check if the key has occurred before
        ++$output[$v];         // increment
    } else {
        $output[$v] = 1;       // declare as 1 on first occurrence
    }
});

var_export($output);

输出:

array (
  1 => 5,
  12 => 2,
  2 => 2,
  13 => 1,
  3 => 1,
)

或者,非递归地:

foreach ($array as $row) {
    foreach ($row as $v) {
        if (isset($output[$v])) { // check if the key has occurred before
            ++$output[$v];        // increment
        } else {
            $output[$v] = 1;      // declare as 1 on first occurrence
        }
    }
}

或者,一个功能性的单线压平然后计数:

var_export(array_count_values(array_reduce($array, 'array_merge', array())));

或者,一个带有 splat 运算符的功能性单行代码,用于展平然后计数:

var_export(array_count_values(array_merge(...$array)));

您可以对该结果使用 call_user_func_array to merge all the individual arrays, and then array_count_values

$data = array
(array(1, 12, 2),
 array(1, 13, 3),
 array(1, 12, 2),
 array(1),
 array(1)
 );

print_r(array_count_values(call_user_func_array('array_merge', $data)));

输出:

Array
(
    [1] => 5
    [12] => 2
    [2] => 2
    [13] => 1
    [3] => 1
)