JSON to PHP array getting "Trying to get property of non-object in" Error

Question

Hello I have Json like this:

[{
    "exam_code": "1",
    "name": "Name1",
    "surname": "Surname1",
    "father_name": "Fname1",
    "id_number": "211111",
    "district_number": "21",
    "school_number": "025",
    "gender": "F",
    "variant": "A",
    "grade": "4",
    "sector": "A",
    "foreign_language": "I",
    "answerList": {
        "gradeFour": {
            "lesson1": ["A", "C", "C", "C", "A", "A", "B", "B", " ", "C", "C", "B", "A", "C", "C", "B", "B", "C", "B", "A"],
            "lesson2": ["B", "A", " ", "C", " ", "B", " ", "B", "B", "C", " ", " ", "B", "A", "A", "A", "C", "A", "B", "B"],
            "lesson3": ["A", "C", "B", "B", "A", "A", "C", "A", "C", "C"],
            "lesson4": ["B", "B", "A", "B", "B"],
            "lesson5": ["B", "A", "A", "B", "B"],
            "lesson6": ["B", "A", "A", "B", "A", "B", "A", "A", "C", "B"]
        }
    }
}]

I am trying to print out lessons answers on foreach loop.

tried below code:

<?php
$msc = microtime(true);


$array = (json_decode($raw_str,true));

foreach($array as $value){
echo $value['id_number'];
    echo '<br/>';

   foreach($value -> answerList->gradeFour as $val){
        echo $val;    
  }

  echo '<br>---------------------------';
  echo '<br>';

}
$msc = microtime(true)-$msc;
echo ($msc * 1000) . ' ms'; // in millseconds
?>

But getting this error

Notice: Trying to get property of non-object in G:\xampp\htdocs\siec\string_test.php on line 50 Notice: Trying to get property of non-object in G:\xampp\htdocs\siec\string_test.php on line 50 Warning: Invalid argument supplied for foreach() in G:\xampp\htdocs\siec\string_test.php on line 50

You start using $value['id_number'] and then switch to object notation access($value -> answerList), you can use one or the other (depending on the second argument to json_decode()) but can't mix them. — Nigel Ren
– Nigel Ren, Commented Nov 11, 2018 at 7:38

Amir · Accepted Answer · 2018-11-11 07:36:54Z

1

In your second foreach loop, $value is an array. So you have to use it with brackets [] not -> :

foreach($value['answerList']['gradeFour'] as $val) {

answered Nov 11, 2018 at 7:36

Amir

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Comments

Moradnejad · Accepted Answer · 2018-11-11 07:48:36Z

0

There are two problems to your code:

First, you have to use brackets instead of ->
Second, you need to use nested loop (two fors) to print the grades, since you have multiple grades (an array) for multiple lessons (another array).

So your complete code will be like this:

$msc = microtime(true);

$array = (json_decode($raw_str,true));

foreach($array as $value){
echo $value['id_number'];
    echo '<br/>';

   foreach($value['answerList']['gradeFour'] as $course){
        foreach($course as $val){
            echo $val;    
        }   
    }

  echo '<br>---------------------------';
  echo '<br>';

}

answered Nov 11, 2018 at 7:48

Moradnejad

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4 Comments

fischer Over a year ago

Thanks for reply... Solved

Moradnejad Over a year ago

@fischer Great. You can accept the answer, as a guide for next visitors.

fischer Over a year ago

is it possible to use foreach($value['answerList']['gradeFour'] as $course){ as foreach($value['answerList'][0] as $course){ because gradefour gradefive it dynamic

Moradnejad Over a year ago

@fischer No, you cant use numbers to access a named array. However, you can iterate on answerList too. like foreach($value['answerList'] as $numberCourses){ and the iterate on $numberCourses to get $course, and so on.

Fathi · Accepted Answer · 2018-11-11 07:54:59Z

0

Your problem in line 5 you must decode it as associative arrays read json_decode

check the code below, it will help you to more understand

 $array = json_decode($raw_str);

 foreach($array as $value){
    echo $value->id_number;
    echo '<br/>';

    foreach($value->answerList->gradeFour as $key => $val){
       echo $key;
       echo "<pre>";
       print_r($val);
       echo "</pre>";

    }

    echo '<br>---------------------------';
    echo '<br>';

}

answered Nov 11, 2018 at 7:54

Fathi

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1 Comment

Moradnejad Over a year ago

This approach adds too much change to the original code: this had to change the way he fetches id_number, and the way he converts from json. Original code obviously wanted array as the result of json_decode, so it is wrong to convert other parts of the code. Also, this answer is simply dumping the whole array of grades and he added pre tag when it is not been asked.

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