Having trouble building nested JSON with PHP - php

Question

I am having trouble getting these arrays to nest properly. I am grabbing all the rows from a SQL database and building an array to output in JSON for my crud app. One category has been easy, but the client now wants subcategories and that's when I hit a major wall. I am trying to nest these subcategories into categories. I can do either, but am failing to get them working together. The following is my PHP code:
while ($row = $query->fetch_assoc()) {
$categories[$row['category']][] = array(
$row['subcategory'] => $subcategories[$row['subcategory']][] = array(
'id' => $row['id'],
'item_name' => $row['item_name'],
'description' => $row['description'],
'price' => $row['price'],
),
);
}
foreach ($categories as $key => $value) {
$category_data[] = array(
'category' => $key,
'category_list' => $value,
);
}
foreach ($subcategories as $key => $value) {
$subcategory_data[] = array(
'subcategory' => $key,
'subcategory_list' => $value,
);
}
When I json_encode($category_data) I get the following JSON:
[
{
"category": "Beer",
"category_list": [
{
"Draft Beer": {
"id": "1",
"item_name": "Yuengling",
"description": "Lager. Pottstown, Pa. An American classic."
}
},
{
"Draft Beer": {
"id": "6",
"item_name": "Bud Light",
"description": "American Light Lager"
}
},
{
"Domestic Bottles": {
"id": "9",
"item_name": "Stone IPA",
"description": "India Pale Ale.<em> Escondido, Colo."
}
}
]
},
{
"category": "Wine",
"category_list": [...]
}
]
Which might work, but I would like it to join the like keys (ie: Draft Beer) into the same array. It does do that when I json_encode($subcategory_data) as shown below, but its not separated into categories, just the subcategories.
[
{
"subcategory": "Draft Beer",
"subcategory_list": [
{
"id": "1",
"item_name": "Yuengling",
"description": "Lager. Pottstown, Pa."
},
{
"id": "6",
"item_name": "Bud Light",
"description": "American Light Lager. Milwaukee, Wisc."
}
]
},
{
"subcategory": "Red Wine",
"subcategory_list": [
{
"id": "17",
"item_name": "Kendall-Jackson",
"description": "Cabernet Sauvignon, 2010."
},
{
"id": "18",
"item_name": "Sanford",
"description": "Pinot Noir, 2011. Lompoc, Calif"
}
]
},
{
"subcategory": "Domestic Bottles",
"subcategory_list": [
{
"id": "9",
"item_name": "Stone IPA",
"description": "India Pale Ale. Escondido, Colo."
},
{
"id": "10",
"item_name": "Blue Moon",
"description": "Belgian-style Wheat Ale."
}
]
}
]
So my question is why does it merge in the second set of data but not the first. How do I get the subcategory_data into the category_data. Any help id truly appreciated. Below is an example if what I am looking for:
{
"category_name":"Beer",
"category_list" : [
{
"subcategory_name": "Draft Beer",
"subcategory_list": [
{
"id": "1",
"item_name": "Yuengling",
"description": "Lager. Pottstown, Pa."
},
{
"id": "6",
"item_name": "Bud Light",
"description": "American Light Lager. Milwaukee, Wisc."
}
}
]
},
{
"category_name":"Wine",
"category_list" : [
{
"subcategory_name": "Red Wine",
"subcategory_list": [...]
}
]
}
Thanks for looking, I am fairly new to PHP and am relying on my javascript skills.

Answer 1

First, try var_dump($categories). You'll see that you're building a rather weird data structure (you have arrays of 1-element arrays...). The following code will build a simpler structure:
$categories[$row['category']][$row['subcategory']][] = array(
'id' => $row['id'],
'item_name' => $row['item_name'],
'description' => $row['description'],
'price' => $row['price'],
);
This will serialize to JSON that's probably acceptable as is:
{
"Beer": {
"Draft Beer": [
{
"id": "1",
"item_name": "Yuengling",
"description": "Lager. Pottstown, Pa."
},
{
"id": "6",
"item_name": "Bud Light",
"description": "American Light Lager. Milwaukee, Wisc."
}
],
...
An additional transformation gets the data in the format you asked for:
foreach ($categories as $category_name => $subcategories) {
$subcategory_data = array();
foreach ($subcategories as $subcategory_name => $items) {
$subcategory_data[] = array(
'subcategory_name' => $subcategory_name,
'subcategory_list' => $items
);
}
$category_data[] = array(
'category_name' => $category_name,
'category_items' => $subcategory_data
);
}