Question

我正在使用关联数组，并将索引作为参数传递给函数。如果我尝试将它们作为参数传递并使用“ print_r”，则该函数将输出数组值及其所有索引而没有问题，我什至可以调用将这些索引的值存储到变量中并在浏览器中输出。

我的问题是，如果我尝试这样编码：

$arr_specimen[$sel_ind1]

浏览器即使先前输出索引及其值，也显示未定义索引错误。该错误的可能解释是什么？如何纠正该错误？这是我的代码：

function array_picker($sel_ind1, $sel_ind2, $sel_ind3, $arr_specimen)
{
    print "$sel_ind1 <br>";
    print "$sel_ind2 <br>";
    print "$sel_ind3 <br>";

    echo "<pre>";
    print_r($arr_specimen);
    echo "</pre>";
}




$selection = array(
    array('fruit' => 'apple', 'normal_price' => 3.75, 'status' => 'discounted'),
    array('fruit' => 'orange', 'normal_price' => 4.15, 'status' => 'non-discounted'),
    array('fruit' => 'grapes', 'normal_price' => 8.35, 'status' => 'discounted'),
    array('fruit' => 'mango', 'normal_price' => 6.65, 'status' => 'discounted'),
    array('fruit' => 'peach', 'normal_price' => 5.45, 'status' => 'non-discounted'),
    array('fruit' => 'kiwi', 'normal_price' => 3.75, 'status' => 'non-discounted'),
    array('fruit' => 'melon', 'normal_price' => 9.05, 'status' => 'non-discounted'),
    array('fruit' => 'pomegranate', 'normal_price' => 7.95, 'status' => 'discounted')
);

 array_picker('fruit', 'normal_price', 'status', $selection);

Answer 1

如代码中所示访问$arr_specimen[$sel_ind1]将访问'fruit'中的索引$arr_specimen，该索引位于下面的$selection中。 $selection不是关联数组，因此没有索引'fruit'。您需要访问数组的第二维，如下所示：$arr_specimen[0][$sel_ind1]，$arr_specimen[1][$sel_ind1]。看看下面的修改后的代码。

function array_picker($sel_ind1, $sel_ind2, $sel_ind3, $arr_specimen)
{
    print "$sel_ind1 <br>";
    print "$sel_ind2 <br>";
    print "$sel_ind3 <br>";

    echo "<pre>";
    print_r($arr_specimen[0][$sel_ind1]); //will get fruit index from first array
    print_r($arr_specimen[1][$sel_ind2]); //will get price index from second array...
    echo "</pre>";
}

Answer 2

正如@AbraCadaver所暗示的，您正在尝试访问整数索引数组（而不是关联数组）的fruit元素。

// your current array
$selection = array(
    array('fruit' => 'apple', 'normal_price' => 3.75, 'status' => 'discounted'),
    array('fruit' => 'orange', 'normal_price' => 4.15, 'status' => 'non-discounted'),
    array('fruit' => 'grapes', 'normal_price' => 8.35, 'status' => 'discounted'),
    array('fruit' => 'mango', 'normal_price' => 6.65, 'status' => 'discounted'),
    array('fruit' => 'peach', 'normal_price' => 5.45, 'status' => 'non-discounted'),
    array('fruit' => 'kiwi', 'normal_price' => 3.75, 'status' => 'non-discounted'),
    array('fruit' => 'melon', 'normal_price' => 9.05, 'status' => 'non-discounted'),
    array('fruit' => 'pomegranate', 'normal_price' => 7.95, 'status' => 'discounted')
);



// to do what you imply by your code
$selection = array(
    'apple'=>array('normal_price' => 3.75, 'status' => 'discounted'),
    'orange'=>array('normal_price' => 4.15, 'status' => 'non-discounted'),
    'grapes'=>array('normal_price' => 8.35, 'status' => 'discounted'),
    'mango'=>array('normal_price' => 6.65, 'status' => 'discounted'),
    'peach'=>array('normal_price' => 5.45, 'status' => 'non-discounted'),
    'kiwi'=>array('normal_price' => 3.75, 'status' => 'non-discounted'),
    'melon'=>array('normal_price' => 9.05, 'status' => 'non-discounted'),
    'pomegranate'=>array('normal_price' => 7.95, 'status' => 'discounted')
);

function array_picker($fruit, $sel_ind2, $sel_ind3, $arr_specimen)
{
    print "{$arr_specimen[$fruit][$sel_ind2]} <br>";
    print "{$arr_specimen[$fruit][$sel_ind3]} <br>";

    echo "<pre>";
    print_r($arr_specimen);
    echo "</pre>";
}

array_picker('apple', 'normal_price', 'status', $selection);

将关联数组的索引传递给函数作为参数

2 个答案: