Question

$requiredKey = ['name', 'type', 'costPrice', 'salePrice'];  
$newArr = ["costPrice" => "45",
        "name" => "133",
        "productType" => "456",
        "remark" => "4545",
        "salePrice" => "454545",
        "saleType" => "789"];
foreach ($requiredKey as $key) {
    if($newArr[$key] == null) {
        //Why this place always is true?
        echo 'null';
        return false;
    }
    $insertData[$key] = $newArr[$key];
}

用于检测值的代码是未设置或为空，有时key的值不为空，但它总是返回true？

Answer 1

isset在大多数情况下都会这样做，array_key_exists更“准确”，因为它也会检测到设置的空值（而不是根本不设置。

isset($a['x']) --> false
array_key_exist('x', $a) --> false
$a['x'] = 1;
isset($a['x']) --> true
array_key_exist('x', $a) --> true
$a['x'] = null;
isset($a['x']) --> false
array_key_exist('x', $a) --> true

Answer 2

您可以改用empty。

$requiredKey = ['name', 'type', 'costPrice', 'salePrice'];  
$newArr = ["costPrice" => "45",
        "name" => "133",
        "productType" => "456",
        "remark" => "4545",
        "salePrice" => "454545",
        "saleType" => "789"];
foreach ($requiredKey as $key) {
    if(empty($newArr[$key])) {
        echo 'null';
        return false;
    }
    $insertData[$key] = $newArr[$key];
}

如果数组键不存在或者数组键存在且值为null，则

empty将返回true。

如何检测数组中的空值或取消设置键？

2 个答案: