Getting JSON data with PHP - php

Question

Apologies if this has been asked a thousand times, but I can't find a good tutorial on how to do this correctly and searching on Stack is coming up trumps.
I have a JSON file which has data like this:
{
"store":"Store 1",
"cat":"Categories",
"general_cat":"Categories",
"spec_cat":"Accessories"
},
{
"store":"Store 1",
"cat":"Categories",
"general_cat":"Categories",
"spec_cat":"Accessories"
},
with about 50 entries in it. I'm trying to parse this data and store the values in variables.
So far I've tried:
$string = file_get_contents("jsonFile.json");
$json_array = json_decode($string,true);
foreach ($json_array as $key => $value){
$store = $key -> store;
$general_cat = $key -> general_cat;
$spec_cat = $key -> spec_cat;
if (!is_null($key -> mainImg_select)){
$cat = $key -> cat;
}
echo $headURL;
}
This is resulting in "Trying to get property of non object" errors. What am I doing wrong here?

Answer 1

The second argument of json_decode tells the function whether to return the data as an object, or an array.
Object access uses the -> symbol. To return an object from json_decode either use json_decode($jsonString) or json_decode($jsonString, false) (the second argument is false by default)
$jsonString = '{ "this_is_json" : "hello!" }';
$obj = json_decode($jsonString);
echo $obj->this_is_json // "hello!";
You can also access your json data as an array by setting the second argument to true
$jsonString = '{ "this_is_json" : "hello!" }';
$arr = json_decode($jsonString, true);
echo $arr['this_is_json'] // "hello!";
What can be a little more conceptually confusing, is that PHP json_decode can return either an array of objects (rather than just an object), or an associative array.
Consider the following json string. This string represents a "collection" (square brackets) of json data structures (curly braces).
[
{
"name": "One"
},
{
"name": "Two"
}
]
If we assign this json to the variable $string hopefully this will illustrate the difference
$asObjects = json_decode($string);
$asAssociativeArray = json_decode($string, true);
foreach ($asObjects as $obj) {
echo $obj->name;
}
foreach ($asAssociativeArray as $arr) {
echo $arr['name'];
}

Answer 2

It seems like you are requesting an associative array (by passing True as the second parameter to the json_decode function) but trying to use it as an object.
Try $json_array = json_decode($string,false); . That will return objects
Also, as #MatRt mentions, you need to use $value instead of $key to reference the objects

Answer 3

You need to retrieve values with array syntax:
$item['key']
as apposed to
$item->key