PHP - 从数组中获取值
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PHP - Get values from Array
提问by CLiown
I am trying to retrieve a value from an Array. Here is the code:
我正在尝试从数组中检索值。这是代码：
$opt=get_records_sql($sql1);
print_object($opt);
$n = count($opt);
if (empty($opt)){
echo 'No options selected';
}
else{
$optno = $opt["subjectid"];
echo '<br>$optno = '.$optno;
}
I tried to use: $opt["subjectid"]but I get the following error:
我尝试使用：$opt["subjectid"]但出现以下错误：
Notice: Undefined index: subjectid
Contents of array:
数组内容：
Array
(
[1] => stdClass Object
(
[uname] => JHollands06
[tutor] => M LSt
[subjectid] => 1
[year] => 2010
[optid] => 1
)
)
How to I fetch the data subjectid which has value 1?
如何获取值为 1 的数据 subjectid？
回答by animuson
Method 1:Convert the object to an array by casting it.
方法 1：通过强制转换将对象转换为数组。
$opt[1] = (array) $opt[1];
echo $opt[1]['subjectid'];
To convert all objects in an array (if there are more than one):
转换数组中的所有对象（如果有多个）：
foreach ($opt as $k => $val) {
$opt[$k] = (array) $val;
}
Method 2:Simply call it as an object like it is already assigned.
方法 2：简单地将它作为一个对象调用，就像它已经被赋值一样。
echo $opt[1]->subjectid
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.
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，数组包含与特定键关联的值。正如您的输出所述，您有一个包含 stdClass 对象的数组，而不是另一个数组。
回答by Tesserex
Your array contains rows. It's not just one row. So you need to index it by row first.
您的数组包含行。这不仅仅是一排。所以你需要先按行索引它。
edit: your rows are objects, my bad. So it should be
编辑：你的行是对象，我不好。所以应该是
$opt[1]->subjectid
$opt[1]->subjectid
回答by Dan
$opt is an array of rows. So you'd do something like this:
$opt 是一个行数组。所以你会做这样的事情：
foreach($opt as $row)
{
echo $row['subjectid'];
}
Or just use an index:
或者只使用索引：
$opt[0]['subjectid'];
