<?php

/**

 * Created by PhpStorm.

 * User: 123456

 * Date: 2018/9/25

 * Time: 19:39

 */

$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',

    )

);

p(array_column2($records,null,'id'));

/**

 * 模仿array_column函数1

 * @param $arr

 * @param $column

 * @param NULL $index_key

 */

function array_column2($arr,$column,$index_key=NULL){

    if ($column && !$index_key){

        foreach ($arr as $key=>$val){

            $data[] = $val[$column];

        }

    }

    if ($index_key){

        foreach ($arr as $key=>$val){

            $data[$val[$index_key]] = $column ? $val[$column] : $val;

        }

    }

    return $data;

}

p(array_column3($records,null,'id'));

/**

 * 模仿array_column函数2

 * @param $arr

 * @param $column_key

 * @param null $index_key

 */

function array_column3($arr,$column_key,$index_key=null){

    $data = array_map(function($d) use ($column_key,$index_key){

//        p($d);

        if ($column_key && ! $index_key){

            return $d[$column_key];

        }

        if ($index_key){

            return [$d[$index_key]=>($column_key === null) ? $d : $d[$column_key]];

        }

    },$arr);

    $tmp=[];

    if ($index_key){

        foreach ($data as $key=>$val){

            $tmp[key($val)] = current($val);

        }

        $data = $tmp;

    }

    return $data;

}

function p($data){

    echo '<pre>';

    print_r($data);

    echo '</pre>';

}