合并多维数组的子数组，同时按字母顺序对数组进行排序

Question

Trying to alphabetically merge arrays with foreach loop.

<?php
$fruits = array(
    'Apple' => array('ids'=>array(1,2)),
    'Banana' => array('ids'=>array(3,4)),
    'Ananas' => array('ids'=>array(5,6))
    );

$result = array();

foreach ($fruits as $name=>$subarr) {
    $first_letter = mb_substr($name, 0, 1);

    $result[$first_letter] = $subarr;
}

print_r($result); gives me smth like

Array
(
    [A] => Array
        (
            [ids] => Array
                (
                    [0] => 5
                    [1] => 6
                )
        )


[B] => Array
    (
        [ids] => Array
            (
                [0] => 3
                [1] => 4
            )
    )


)

instead of smth like

\n    [A] => Array \n        ( \n            [ids] => Array \n                ( \n                    [0] => 1 \n                    [1] => 2 \n                    [2] => 5 \n                    [3] => 6 \n                ) \n        ) \n

how can I fix it?

Answer 1

You overwrite your result every iteration in this line:

$result[$first_letter] = $subarr;

Just create a new array if the subArray in the result array doesn't exists and merge the ids subArray into your result array.

foreach ($fruits as $name=>$subarr) {
    $first_letter = mb_substr($name, 0, 1);

    if(!isset($result[$first_letter]))
        $result[$first_letter] = [];
    $result[$first_letter] = array_merge($result[$first_letter], $subarr["ids"]);
}

Answer 2

Please try to use foreach loop.

$fruits = array(
    'Apple' => array('ids'=>array(1,2)),
    'Banana' => array('ids'=>array(3,4)),
    'Ananas' => array('ids'=>array(5,6))
    );

$result = array();
foreach ($fruits as $name=>$subarr) {
    $first_letter = mb_substr($name, 0, 1);
    foreach($subarr as $key=>$value){
        foreach ($value as $gkey => $gvalue) {
            $result[$first_letter]['ids'][] = $gvalue;
        }

    }
}

echo "<pre>";
print_r($result);

Display above code output like below.

Array
(
    [A] => Array
        (
            [ids] => Array
                (
                    [0] => 1
                    [1] => 2
                    [2] => 5
                    [3] => 6
                )

        )

    [B] => Array
        (
            [ids] => Array
                (
                    [0] => 3
                    [1] => 4
                )

        )

)