Error “Cannot use object of type stdClass as array” when accessing a clearly existing, integer type data from Laravel Database query result

问题

I got my data from Laravel database query command:

$group = DB::table('groups')->where("id", $group_id)->first();

When I var dump my data, I get:

object(stdClass)#200 (7) {
  ["id"]=>
  int(1)
  ["levels_id"]=>
  int(1)
  ["title"]=>
  string(8) "Novice 1"
  ["description"]=>
  string(11) "Lorem Ipsum"
  ["max_question_display"]=>
  int(5)
  ["created_at"]=>
  NULL
  ["updated_at"]=>
  NULL
}

I want to access the max_question_display. But when I do:

var_dump($group["max_question_display"]);

PHP returns error Cannot use object of type stdClass as array.

When I do:

var_dump($group->max_question_display);

I get:

int(5)

But I don't want the int. I only want the 5. In integer form.

If I foreach loop the $group:

foreach ($group as $t) {
    echo "<pre>";
    var_dump($t);
    echo "</pre>";
}

I get each of the data as a single data each loop.

int(1)
int(1)
string(8) "Novice 1"
string(11) "Lorem Ipsum"
int(5)
NULL
NULL

This is obviously also not the way the result accessed that I'm looking for.

I also tried to get the first element of array, thinking that this might be an array with 1 element, but that also raise the same error.

I get it that the general answer in this site about this error is that "stdClass is not array". I have browsed several question with similar title like mine, but nothing address object that came from Laravel DB. When I read the manual on Laravel DB, I was assured that I can access the data returned like a simple dictionary / hashmap.

EDIT: Sorry, I understand my very, very newbie mistakes. No need to answer this. Thanks.

回答1:

Notice the first line of your first var_dump:

object(stdClass)#200

Because you're dealing with an object, you access its properties with ->. When you do:

var_dump($group->max_question_display);

The reason you see (int) in the output is that the var_dump function shows the value type, next to the value. To access the value, do

$group->max_question_display;

If you want to see it on screen without the type, use echo

echo $group->max_question_display; // 5

回答2:

stdClass is an object. You cannot use an object with array syntax to access its properties, if the class does not implement ArrayAccess interface.

As pointed out by @IbrahimLawal , var_dump outputs both the type and value. Just echoing $group->max_question_display will provide just the value

echo $group->max_question_display; // 5

In Summary: You must use arrow syntax when interacting with stdClass.

来源：https://stackoverflow.com/questions/38543175/error-cannot-use-object-of-type-stdclass-as-array-when-accessing-a-clearly-exi

标签

php

arrays

database

laravel

hashmap