PHP - 未定义的偏移量：0
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PHP - undefined offset: 0
提问by Gravy
print_r($p->attachments)produces:
print_r($p->attachments)产生：
Array
(
[0] => stdClass Object
(
[id] => ...
[url] => http://...png
[slug] => ...
[title] => ...
[description] => ...
[caption] => ...
[parent] => ...
[mime_type] => image/png
[images] => ...
(
)
)
)
I wish to access the value in the urlfield
我希望访问该url字段中的值
print_r($p->attachments[0]->url)retrieves the url, but also produces: Undefined offset: 0
print_r($p->attachments[0]->url)检索网址，但也会产生： Undefined offset: 0
Now I can supress the error by calling print_r(@$p->attachments[0]->url), but is there a proper way of fixing this?
现在我可以通过调用来抑制错误print_r(@$p->attachments[0]->url)，但是有没有正确的方法来解决这个问题？
I am not able to modify the $p object.
我无法修改 $p 对象。
Edit:
编辑：
As suggested, here is response from Var_dump($p->attachments)
正如所建议的，这是来自 Var_dump($p->attachments) 的回应
array(1) {
[0]=>
object(stdClass)#322 (9) {
["id"]=>
int(1814)
["url"]=>
string(76) "..."
["slug"]=>
string(34) "..."
["title"]=>
string(34) "..."
["description"]=>
string(0) ""
["caption"]=>
string(53) "..."
["parent"]=>
int(1811)
["mime_type"]=>
string(9) "image/png"
["images"]=>
array(0) {
}
}
}
回答by Suvash sarker
You can use isset() for check the array:
您可以使用 isset() 检查数组：
if(isset($p->attachments[0])){
echo $p->attachments[0]->url;
}
else {
//some error?
}
Or if you know that you are only going to be checking index 0 then you can do this way
或者，如果您知道您只会检查索引 0，那么您可以这样做
$array = $array + array(null);
So if the original $array[0] was unset, now it is null
所以如果原来的 $array[0] 没有设置，现在它是空的
回答by halfik
dunno why it returns you a value and informs you that there is undefined offset 0. strange.
不知道为什么它会返回一个值并通知您有未定义的偏移量 0。奇怪。
can you check this (since attachments is an array you should do this that way):
你能检查一下吗（因为附件是一个数组，你应该这样做）：
if ( count($p->attachments) > 0 ){
foreach ($p->attachments AS $att){
//do the stuff if attachement
}
}
