How to convert a two-dimensional array to a one-dimensional array in php

The method to convert a two-dimensional array into a one-dimensional array in PHP is: you can use the array_column() function to achieve this. This function returns an array whose value is the value of a single column in the input array. The specific method is: [array_column($records, 'first_name')].

Related function introduction:

(Recommended tutorial: php tutorial)

array_column() The function returns an array whose value is the value of a single column in the input array.

Function syntax:

array_column(array,column_key,index_key);

Parameter description:

• array Required. Specifies the multidimensional array (record set) to use.

• column_key Required. The column whose value needs to be returned. Can be an integer index of a column of an index array, or a string key value of a column of an associative array. This parameter can also be NULL, in which case the entire array will be returned (very useful when used with the index_key parameter to reset the array key).

• #index_key Optional. The column that is the index/key of the returned array.

The following array exists:

$records = [
    [
        'id' => 2135,
        'first_name' => 'John',
        'last_name' => 'Doe',
    ],
    [
        'id' => 3245,
        'first_name' => 'Sally',
        'last_name' => 'Smith',
    ],
    [
        'id' => 5342,
        'first_name' => 'Jane',
        'last_name' => 'Jones',
    ],
    [
        'id' => 5623,
        'first_name' => 'Peter',
        'last_name' => 'Doe',
    ]
];

Code implementation:

Example 1:

<?php　　
    $first_names = array_column($records, &#39;first_name&#39;);
　　var_dump($first_names);
?>

Print result:

$first_names = ['John','Sally','Jane','Peter'];

Example 2:

<?php
　　$first_names = array_column($records, &#39;first_name&#39;，&#39;id&#39;);
　　var_dump($first_names);
?>

Print result:

$first_names = [2135 =>'John',3245 => 'Sally',5342 => 'Jane',5623 => 'Peter'];

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