如何计算PHP中多维数组中值的出现

Question

First pardon me for the title as I couldn't find a proper title for it. Please have a look at the array

Array
(
[0] => Array
    (
        [0] => 2017
        [1] => Array
            (
                [0] => December
            )

    )

[1] => Array
    (
        [0] => 2017
        [1] => Array
            (
                [0] => December
            )

    )

[2] => Array
    (
        [0] => 2017
        [1] => Array
            (
                [0] => October
            )

    )

[3] => Array
    (
        [0] => 2016
        [1] => Array
            (
                [0] => December
            )

    )

 )

You can see 2017 is duplicated three times and inside 2017 December is duplicated two times. Now I want to get a multi dimensional array from this array that will show the occurrence of 2017 and it's month.

Something like

Array
(
  [2017] => 3
  [December]=> 2 // should be a nested array of 2017
  [October]=> 1 // should be a nested array of 2017
  [2016] => 1
  [December]=> 1 // should be a nested array of 2016
)

I tried array_count_values and some more custom code but all I managed to get

Array
(
[2017] => 3
[2016] => 1
)

Edit: The months count doesn't has be keyed like this. All I need to know year occurrence and month occurrence under the year

Any help is highly appreciated. Thanks.

Answer 1

You can try to loop then check if year key and month key already exist

$group = [];
foreach ($array as $value) {
    $month = $value[1][0];
    if (!isset($group[$value[0]])) {
        $group[$value[0]] = array('count' => 0);
    }
    if (!isset($group[$value[0]][$month])) {
        $group[$value[0]][$month] = 0;
    }
    $group[$value[0]][$month] += 1;
    $group[$value[0]]['count'] += 1;
}

print_r($group);

If you don't necessarily need the count, you can change the first if condition 's execution to $group[$value[0]] = array(); and the line $group[$value[0]]['count'] += 1;

foreach ($array as $value) {
    $month = $value[1][0];
    if (!isset($group[$value[0]])) {
        $group[$value[0]] = array();
    }
    if (!isset($group[$value[0]][$month])) {
        $group[$value[0]][$month] = 0;
    }
    $group[$value[0]][$month] += 1;
}

print_r($group);