Make array_column () functions compatible with PHP earlier versions

Make array_column () functions compatible with PHP earlier versions

Array_column () is a very useful php Data function. It is mainly used to obtain a set of values in a column of a two-dimensional array and then form a new array, however, this function only supports php 5.5 and later versions. Therefore, we provide an implementation method for php 5.5 and later versions.

if(!function_exists('array_column')){    function array_column($arr,$key){        return array_map(function($val) use ($key){            return $val[$key];        },$arr);    }}

Or:

if(!function_exists('array_column')){    function array_column($input,$column_key,$index_key=null){        $arr=array_map(function($d) use ($column_key,$index_key){            if(!isset($d[$column_key])){                return null;            }            if($index_key!==null){                return array($d[$index_key]=>$d[$column_key]);            }            return $d[$column_key];        },$input);        if($index_key!==null){            $tmp=array();            foreach ($arr as $ar){                $tmp[key($ar)]=current($ar);            }            $arr=$tmp;        }        return $arr;    }}

Example:

<?php$records = array(    array(        'id' => 2135,        'first_name' => 'John',        'last_name' => 'Doe',    ),    array(        'id' => 3245,        'first_name' => 'Sally',        'last_name' => 'Smith',    ),    array(        'id' => 5342,        'first_name' => 'Jane',        'last_name' => 'Jones',    ),    array(        'id' => 5623,        'first_name' => 'Peter',        'last_name' => 'Doe',    )); $first_names = array_column($records, 'first_name');print_r($first_names);

The above routine will output:

Array
(
[0] => John
[1] => Sally
[2] => Jane
[3] => Peter
)