PHP array learning: How to reset the index of a multi-dimensional array

In the previous article "PHP Array Learning: How to Remove Blank or Duplicate Elements", we introduced the method of empty and duplicate elements in the array, that is, the method of deleting empty elements and duplicate elements in the array. Let’s briefly talk about the method of resetting the one-dimensional array index. The index of a one-dimensional array can be reset, but how to reset the index of a two-dimensional array or even a multi-dimensional array? Let’s introduce the method below.

→Related recommendations: 《PHP array learning series summary (continuously updated~)》

First of all, we know from the above that one-dimensional If you want to reset the index of an array, it is very simple. Just use the array_values($array) function.

array_values() function is to return the values ​​of all elements in the array. It is very simple to use. With only one required parameter $array, it can return a value containing all elements in the given array. Array of values, but no key names. The returned array will be in the form of an indexed array, with array indices starting at 0 and increasing by 1.

We can use the array_values() function to rearrange the array with chaotic element subscripts, that is, the index starts from 0 and increases by 1; this function can not only be used to index arrays, but also to associate Array can convert an associative array into an indexed array.

To reset the index of a multi-dimensional array, you also need to use the array_values() function. Below we directly give the implementation method:

function reform_keys($array){
    if(!is_array($array)){
        return $array;
    }
    $keys = implode('', array_keys($array));
    if(is_numeric($keys)){
        $array = array_values($array);
    }
    $array = array_map('reform_keys', $array);
    return $array;
};

Test it, there is the following multi-dimensional array

$post = [
    0 => [
        'title' => 'xxx联票',
        'price' => 368.00,
        'items' => [
            '33' => [
                'scenic_id' => 33,
                'products' => [
                    'goods_id' => 13
                ]
            ],
            '1500' => [
                'scenic_id' => 1500,
                'products' => [
                    'goods_id' => 57
                ]
            ],
        ],
        'tickets' => 9
    ],
    10 => [
        'title' => 'zzz联票',
        'price' => 500.00,
        'items' => [
            '157' => [
                'scenic_id' => 157,
                'products' => [
                    'goods_id' => 77
                ],
                'attr' => [
                    '50' => [
                        'item' => '午场'
                    ],
                    '55' => [
                        'item' => '可退'
                    ]
                ]
            ],
            '19' => [
                'scenic_id' => 19,
                'products' => [
                    'goods_id' => 87
                ]
            ]
        ],
        'tickets' => 3
    ],
];

Call the reform_keys() function to reset the index of the $post array, and output the reset array :

$list = reform_keys($post);
var_dump($list);

The output result is:

It can be seen that the indexes of all levels in the multi-dimensional array $post have been reset, starting from 0 The count begins!

Let me introduce to you the functions used in it:

• array_keys($array): Get all the key names in the $array array;

• $keys=implode('', array_keys($array)): Splice the elements in the key array together and return a string $keys.

• is_numeric($keys): Check whether the variable $keys is a number or a numeric string.

• array_values($array): Get all values, that is, reset the index;

• ##array_map( 'reform_keys', $array): Apply the callback function reform_keys() to each element of the $array array.

  array_map() returns an array. The contents of the array are the elements of array1 and the result of calling callback for the parameters in index order (when there are more arrays, the elements of arrays will also be passed in). The number of callback function parameters must match the number of arrays in the array_map() argument.

  
  

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