问题描述
我正在尝试从数组中检索值。下面是代码:
I am trying to retrieve a value from an Array. Here is the code:
$opt=get_records_sql($sql1);
print_object($opt);
$n = count($opt);
if (empty($opt)){
echo 'No options selected';
}
else{
$optno = $opt["subjectid"];
echo '<br>$optno = '.$optno;
}
我尝试使用: $ opt [ subjectid ]
,但出现以下错误:
I tried to use: $opt["subjectid"]
but I get the following error:
Notice: Undefined index: subjectid
数组内容:
Array
(
[1] => stdClass Object
(
[uname] => JHollands06
[tutor] => M LSt
[subjectid] => 1
[year] => 2010
[optid] => 1
)
)
如何获取值为1的数据主题?
How to I fetch the data subjectid which has value 1?
推荐答案
方法1:通过强制转换将对象转换为数组。
Method 1: Convert the object to an array by casting it.
$opt[1] = (array) $opt[1];
echo $opt[1]['subjectid'];
要转换数组中的所有对象(如果有多个):
To convert all objects in an array (if there are more than one):
foreach ($opt as $k => $val) {
$opt[$k] = (array) $val;
}
方法2:只需将其称为对象
echo $opt[1]->subjectid
数组和对象之间是有区别的。对象包含必须使用->调用的变量,而数组包含与特定键相关联的值。作为输出状态,您有一个包含stdClass对象的数组,而不是另一个数组。
There is a difference between an array and an object. An object contains variables that have to be called using the '->' and an array contains values which are associated with a specific key. As your output states, you have an array containing an stdClass object, not another array.
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