如何防止array_merge重新编号数字键

Question

我有一个看起来像这样的数组:

Array ( 
    [0] => Array ( [unit_id] => 1 [unit_name] => Clown Fish) 
    [1] => Array ( [unit_id] => L [unit_name] => Liter ) 
    [2] => Array ( [unit_id] => 2 [unit_name] => Elephant  ) 
    [3] => Array ( [unit_id] => 3 [unit_name] => Water Bottle ) 
    [4] => Array ( [unit_id] => 4 [unit_name] => Office Seating ) 
    [5] => Array ( [unit_id] => 5 [unit_name] => Green Green Grass ) 
)

然后,我写了一个函数

function array_to_list($arr_data, $str_key, $str_value) {
    $arr_list = array();
    if (is_array($arr_data)) {
        foreach($arr_data as $arr_value) {
            if (isset($arr_value[$str_key]) && isset($arr_value[$str_value])) {
                $arr_list = array_merge($arr_list, array($arr_value[$str_key] => $arr_value[$str_value]));
            }
        }
    }
    return $arr_list;
}

将数组转换为如下所示

Array ( 
    [1] => Clown Fish ) 
    [L] => Liter ) 
    [2] => Elephant ) 
    [3] => Water Bottle ) 
    [4] => Office Seating ) 
    [5] => Green Green Grass ) 
)

但输出却是

Array ( 
    [0] => Clown Fish ) 
    [L] => Liter ) 
    [1] => Elephant ) 
    [2] => Water Bottle ) 
    [3] => Office Seating ) 
    [4] => Green Green Grass ) 
)

我认为这与array_merge本身的性质有关,根据php手册"输入数组中带有数字键的值将使用从结果数组中的零开始的递增键重新编号."

有没有办法让我能用或不用array_merge产生预期的结果？

Answer 1

使用'+'运算符代替array_merge():

function array_to_list($arr_data, $str_key, $str_value) {
$arr_list = array();
if (is_array($arr_data)) {
    foreach($arr_data as $arr_value) {
        if (isset($arr_value[$str_key]) && isset($arr_value[$str_value])) {
            $arr_list = $arr_list + array($arr_value[$str_key] => $arr_value[$str_value]);
        }
    }
}
return $arr_list;

}

Answer 2

为什么不尝试一种更简单的方法：

function array_to_list($arr_data, $str_key, $str_value) {
    $arr_list = array();
    if (is_array($arr_data)) {
        foreach($arr_data as $arr_value) {
            if (isset($arr_value[$str_key]) && isset($arr_value[$str_value])) {

                // This is the changed line:
                $arr_list[ $arr_value[$str_key] ] = $arr_value[$str_value];

            }
        }
    }
    return $arr_list;
}

这只是直接在输出数组上设置值。没有理由每次都创建一个新数组并合并它。它也应该快一点。