获取 PHP stdObject 中的第一个元素
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Get first element in PHP stdObject
提问by Drew Baker
I have an object (stored as $videos) that looks like this
我有一个看起来像这样的对象（存储为 $videos）
object(stdClass)#19 (3) {
[0]=>
object(stdClass)#20 (22) {
["id"]=>
string(1) "123"
etc...
I want to get the ID of just that first element, without having to loop over it.
我只想获取第一个元素的 ID，而不必遍历它。
If it were an array, I would do this:
如果它是一个数组，我会这样做：
$videos[0]['id']
It used to work as this:
它曾经是这样工作的：
$videos[0]->id
But now I get an error "Cannot use object of type stdClass as array..." on the line shown above. Possibly due to a PHP upgrade.
但是现在我在上面显示的行上收到错误“无法使用 stdClass 类型的对象作为数组...”。可能是由于 PHP 升级。
So how do I get to that first ID without looping? Is it possible?
那么如何在不循环的情况下获得第一个 ID？是否可以？
Thanks!
谢谢！
回答by MrTrick
Both array() and the stdClass objects can be accessed using the
current()key()next()prev()reset()end()functions.
array() 和 stdClass 对象都可以使用这些
函数访问
。current()key()next()prev()reset()end()
So, if your object looks like
所以，如果你的对象看起来像
object(stdClass)#19 (3) {
[0]=>
object(stdClass)#20 (22) {
["id"]=>
string(1) "123"
etc...
Then you can just do;
然后你就可以了；
$id = reset($obj)->id; //Gets the 'id' attr of the first entry in the object
If you need the key for some reason, you can do;
如果您出于某种原因需要密钥，您可以这样做；
reset($obj); //Ensure that we're at the first element
$key = key($obj);
Hope that works for you. :-) No errors, even in super-strict mode, on PHP 5.4
希望这对你有用。:-) 在 PHP 5.4 上没有错误，即使在超级严格模式下
回答by Clain Dsilva
Update 2019
2019 年更新
Moving on to the best practices of OOPS, @MrTrick's answer must be marked as correct, although my answer provides a hacked solution its not the best method.
转到 OOPS 的最佳实践，@MrTrick 的答案必须标记为正确，尽管我的答案提供了一个破解解决方案，但它不是最佳方法。
Simply iterate its using {}
只需使用 {} 对其进行迭代
Example:
例子：
$videos{0}->id
This way your object is not destroyed and you can easily iterate through object.
这样您的对象就不会被破坏，您可以轻松地遍历对象。
For PHP 5.6 and below use this
对于 PHP 5.6 及以下，请使用此
$videos{0}['id']
回答by froilanq
Correct:
正确的：
$videos= (Array)$videos;
$video = $videos[0];
回答by Patrick
much easier:
容易得多：
$firstProp = current( (Array)$object );
回答by Biraj Bora
$videos->{0}->idworked for me.
$videos->{0}->id为我工作。
Since $videos and {0} both are objects, so we have to access id with $videos->{0}->id. The curly braces are required around 0, as omitting the braces will produce a syntax error : unexpected '0', expecting identifier or variable or '{' or '$'.
由于 $videos 和 {0} 都是对象，所以我们必须使用 $videos->{0}->id. 大括号需要在 0 左右，因为省略大括号会产生语法错误：意外的 '0'，需要标识符或变量或 '{' 或 '$'。
I'm using PHP 5.4.3.
我正在使用PHP 5.4.3。
In my case, neither $videos{0}->idand $videos{0}['id']worked and shows error :
在我的情况下，既没有$videos{0}->id和$videos{0}['id']合作，并显示错误：
Cannot use object of type stdClass as array.
不能使用 stdClass 类型的对象作为数组。
回答by Rolf
You could loop on the object maybe and break in the first loop... Something like
你可以在对象上循环，然后在第一个循环中中断......就像
foreach($obj as $prop) {
$first_prop = $prop;
break; // exits the foreach loop
}
回答by Thomas Decaux
Playing with Php interactive shell, Php 7:
玩 PHP 交互式 shell，Php 7：
? ~ php -a
Interactive shell
php > $v = (object) ["toto" => "hello"];
php > var_dump($v);
object(stdClass)#1 (1) {
["toto"]=>
string(5) "hello"
}
php > echo $v{0};
PHP Warning: Uncaught Error: Cannot use object of type stdClass as array in php shell code:1
Stack trace:
#0 {main}
thrown in php shell code on line 1
Warning: Uncaught Error: Cannot use object of type stdClass as array in php shell code:1
Stack trace:
#0 {main}
thrown in php shell code on line 1
php > echo $v->{0};
PHP Notice: Undefined property: stdClass::##代码## in php shell code on line 1
Notice: Undefined property: stdClass::##代码## in php shell code on line 1
php > echo current($v);
hello
Only currentis working with object.
仅current与对象一起工作。
