Get 3 element per category From array in PHP - php

Question

I have 2 arrays category and product_to_category (Structure shown below)
[category] => Array
(
[0] => 299
[2] => 342
[3] => 134
[4] => 333
[5] => 347
[9] => 296
)
And
[product_to_category] => Array
(
[0] => Array
(
[product_id] => 23895
[category_id] => 296
[relevance] => 77.73432159423828
)
[1] => Array
(
[product_id] => 17218
[category_id] => 296
[relevance] => 77.73432159423828
)
[2] => Array
(
[product_id] => 23896
[category_id] => 347
[relevance] => 77.73432159423828
)
....So On (5000+ records)
i have almost 5000+ records in product_to_category array, But i want to pick only 3 products from P2C array per Category. For Example category_id=299 so 3 products of 299 will be added to my new array and same for other categories.
Is there any possible way to do that .

Answer 1

Try this query to fetch record you wanted,
select p2c.product_id, p2c.category_id, p2c.relevance
from category c
LEFT JOIN product_to_category p2c ON p2c.category_id = category.category_id
GROUP BY p2c.product_id, p2c.category_id
HAVING count(*) <= 3
ORDER BY category_id, product_id
You can refer table category to category table and product_to_category to your table name in database.

Answer 2

$category = [0 => 299, 2 => 342, 3 => 134, 4 => 333, 5 => 347, 9 => 296];
$product_to_category = Array
(
0 => Array
(
'product_id' => 23895,
'category_id' => 296,
'relevance' => 77.73432159423828
),
1 => Array
(
'product_id' => 17218,
'category_id' => 296,
'relevance' => 77.73432159423828
),
2 => Array
(
'product_id' => 23896,
'category_id' => 347,
'relevance' => 77.73432159423828
),
3 => Array
(
'product_id' => 23897,
'category_id' => 296,
'relevance' => 77.73432159423828
),
4 => Array
(
'product_id' => 23899,
'category_id' => 296,
'relevance' => 77.73432159423828
),
5 => Array
(
'product_id' => 23894,
'category_id' => 347,
'relevance' => 77.73432159423828
),
6 => Array
(
'product_id' => 23892,
'category_id' => 347,
'relevance' => 77.73432159423828
),
7 => Array
(
'product_id' => 23833,
'category_id' => 347,
'relevance' => 77.73432159423828
)
);
$new_product_to_category = [];
foreach ($category as $categories) {
$count_category_ids = [];
$i=0;
foreach ($product_to_category as $product_to_categories){
if ($categories == $product_to_categories['category_id']){
$count_category_ids[] = $product_to_categories['category_id'];
if (count($count_category_ids) < 4) {
$new_product_to_category[$i]['product_id'] = $product_to_categories['product_id'];
$new_product_to_category[$i]['category_id'] = $product_to_categories['category_id'];
$new_product_to_category[$i]['relevance'] = $product_to_categories['relevance'];
}
}
$i++;
}
}
echo "<pre>";
print_r($new_product_to_category);
Output shows like this :
Array
(
[2] => Array
(
[product_id] => 23896
[category_id] => 347
[relevance] => 77.734321594238
)
[5] => Array
(
[product_id] => 23894
[category_id] => 347
[relevance] => 77.734321594238
)
[6] => Array
(
[product_id] => 23892
[category_id] => 347
[relevance] => 77.734321594238
)
[0] => Array
(
[product_id] => 23895
[category_id] => 296
[relevance] => 77.734321594238
)
[1] => Array
(
[product_id] => 17218
[category_id] => 296
[relevance] => 77.734321594238
)
[3] => Array
(
[product_id] => 23897
[category_id] => 296
[relevance] => 77.734321594238
)
)

Answer 3

$categories = array(6, 5, 3, 4, 2, 1);
$products = array(
array('product_id' => 231, 'category_id' => 1, 'relevance' => 321),
array('product_id' => 232, 'category_id' => 4, 'relevance' => 322),
array('product_id' => 233, 'category_id' => 2, 'relevance' => 323),
array('product_id' => 234, 'category_id' => 4, 'relevance' => 324),
array('product_id' => 235, 'category_id' => 4, 'relevance' => 325),
array('product_id' => 236, 'category_id' => 2, 'relevance' => 326),
array('product_id' => 237, 'category_id' => 1, 'relevance' => 327),
array('product_id' => 238, 'category_id' => 4, 'relevance' => 328),
array('product_id' => 239, 'category_id' => 1, 'relevance' => 329),
array('product_id' => 240, 'category_id' => 1, 'relevance' => 330)
);
$categoryWiseProduct = array();
foreach ($products as $p) {
foreach ($categories as $c) {
if ($c == $p['category_id']) {
if (isset($categoryWiseProduct[$c]) && count($categoryWiseProduct[$c]) > 2) {
break;
}
$categoryWiseProduct[$c][] = $p;
}
}
}
echo'<pre>';print_r($categoryWiseProduct);die;
Output will be:
Array
(
[1] => Array
(
[0] => Array
(
[product_id] => 231
[category_id] => 1
[relevance] => 321
)
[1] => Array
(
[product_id] => 237
[category_id] => 1
[relevance] => 327
)
[2] => Array
(
[product_id] => 239
[category_id] => 1
[relevance] => 329
)
)
[4] => Array
(
[0] => Array
(
[product_id] => 232
[category_id] => 4
[relevance] => 322
)
[1] => Array
(
[product_id] => 234
[category_id] => 4
[relevance] => 324
)
[2] => Array
(
[product_id] => 235
[category_id] => 4
[relevance] => 325
)
)
[2] => Array
(
[0] => Array
(
[product_id] => 233
[category_id] => 2
[relevance] => 323
)
[1] => Array
(
[product_id] => 236
[category_id] => 2
[relevance] => 326
)
)
)

Answer 4

try this code
$collection = array();
foreach($arr as $key => $value){
if(
isset($collection[$value['category_id']])
&&
count($collection[$value['category_id']]) >= 3
) continue;
$collection[$value['product_id']][] = $value['product_id'];
}
In this way, you will get 3 products from each category.
You can add more condition if you need, like check the product id you can use inside if condition
&& in_array($product_id, $collection[$value['category_id']])