php嵌套数组爆炸

Question

Hi one of my column in table has data like

category1_subcat_1
category1_subcat_2
category1_subcat_3
category2_subcat_1
category2_subcat_2
category3_subcat_1
category3_subcat_3

I want to convert it to nested array like

category1
 subcat1
 subcat2
 subcat3

category2
 subcat1
 subcat2

category3
 subcat1
 subcat3

i tried

foreach ($categories as $category){     

 $cat_array = explode("_",$category['cat_subcat']);
 $cat_subcat = array(
        'cat'=>$cat_array[0],
        'subcat'=>$cat_array[1]
        );
}

but how do i group this by category please help

Answer 1

Try this..

<?php

$categories = [
    ['cat_subcat' => 'category1_subcat_1'],
    ['cat_subcat' => 'category1_subcat_2'],
    ['cat_subcat' => 'category1_subcat_3'],
    ['cat_subcat' => 'category2_subcat_1'],
    ['cat_subcat' => 'category2_subcat_2'],
    ['cat_subcat' => 'category3_subcat_1'],
    ['cat_subcat' => 'category3_subcat_3']
];

$finalCategories = [];

foreach ($categories as $category){
    $cat_array = explode("_",$category['cat_subcat']);
    $finalCategories[$cat_array[0]][] = $cat_array[1] . $cat_array[2];
}

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

The output will be..

Array
(
    [category1] => Array
        (
            [0] => subcat1
            [1] => subcat2
            [2] => subcat3
        )

    [category2] => Array
        (
            [0] => subcat1
            [1] => subcat2
        )

    [category3] => Array
        (
            [0] => subcat1
            [1] => subcat3
        )

)

Add the following lines of code..

// Adding another loop
$output = [];
$i = 0;
foreach ($finalCategories as $category => $subCategories) {
    $output[$i]['cat_name'] = $category;
    foreach ($subCategories as $subCategory) {
        $output[$i]['sub_cat'][] = $subCategory;
    }
    $i++;
}

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

New Ouptut..

Array
(
    [0] => Array
        (
            [cat_name] => category1
            [sub_cat] => Array
                (
                    [0] => subcat1
                    [1] => subcat2
                    [2] => subcat3
                )

        )

    [1] => Array
        (
            [cat_name] => category2
            [sub_cat] => Array
                (
                    [0] => subcat1
                    [1] => subcat2
                )

        )

    [2] => Array
        (
            [cat_name] => category3
            [sub_cat] => Array
                (
                    [0] => subcat1
                    [1] => subcat3
                )

        )

)