PHP-筛选两个数组的最有效方法

Question

I have a question on what is the most performant way to filter two arrays of objects. I have two arrays of products from different systems and i want to work out which products have been removed from one array and then return the products that have been removed.

See the current function i have below which i know is super slow.

 public function checkRemove($externalProducts, $localProducts){
    //Push all the SKU codes from feed to an array();
    $arr = [];
    foreach ($externalProducts->products as $product) {
        if($product->StockNumber != null){
            array_push($arr, $product->StockNumber);
        }
    }
    //Loop through the local products 
    $productsRemove = [];
    foreach ($localProducts->products as $key => $localProduct) {
        if(in_array($localProduct->sku, $arr)){

        }else{
            array_push($productsRemove, $localProduct);
        }
    }    
    return $productsRemove;
}

$externalProducts = {
"Filter": {
    "Title": "All Products"
},
"Products": [{
        "Type": "Jacket",
        "Price": 75,
        "ExpiryDate": "2018-06-30",
        "StockNumber": "180220/003",
        "Created": "2018-02-20 12:24:06",
        "Modified": "2018-05-30 02:00:23"
    },
    {
        "Type": "Jeans",
        "Price": 150,
        "ExpiryDate": "2018-06-30",
        "StockNumber": "180221/004",
        "Created": "2017-08-10 15:11:44",
        "Modified": "2018-05-30 02:00:22"
    },
    {
        "Type": "Jacket",
        "Price": 240,
        "ExpiryDate": "2018-06-30",
        "StockNumber": "150804/012",
        "Created": "2015-08-04 17:03:42",
        "Modified": "2018-05-30 02:00:22"
    }
    ]
}
$internalProducts = "localProducts": [{
    "title": "Fur Coat",
    "id": 16526,
    "created_at": "2018-05-17T10:15:45Z",
    "updated_at": "2018-05-17T10:15:45Z",
    "sku": "180514/001",
    "price": "75.00",
    "regular_price": "75.00",
    "categories": [
        "Jackets",
    ],
},
{
    "title": "Ripped Jeans",
    "id": 16527,
    "created_at": "2018-05-17T10:15:45Z",
    "updated_at": "2018-05-17T10:15:45Z",
    "sku": "180221/004",
    "price": "150.00",
    "regular_price": "150.00",
    "categories": [
        "Jeans",
    ],
},
{
    "title": "Leather Jacket",
    "id": 16528,
    "created_at": "2018-05-17T10:15:45Z",
    "updated_at": "2018-05-17T10:15:45Z",
    "sku": "150804/012",
    "price": "240.00",
    "regular_price": "240.00",
    "categories": [
        "Jackets",
    ],
    }
]

Answer 1

Take a look at array_filter

You can provide a callback function which will be run for each element in the array. If the callback function returns true, the current value from the array is returned in the result array.

Answer 2

You still have to iterate over one array at least. It is $localProducts . So, for $localProducts there're no improvements. But you can improve $externalProducts - add a special method (if you can) that will return StockNumbers only. More effective will be if StockNumbers will be of structure as:

[
    'stocknumber1' => true,
    'stocknumber2' => true,
    'stocknumber3' => true,
    'stocknumber4' => true,
    'stocknumber5' => true,
]

This will improve your search, as checking isset($StockNumbers['stocknumber4']) is faster than in_array or array_search .

If you can't change structure of $externalProducts->products , than build array of stock numbers in a loop:

public function checkRemove($externalProducts, $localProducts){
    //Push all the SKU codes from feed to an array();
    $arr = [];
    foreach ($externalProducts->products as $product) {
        if ($product->StockNumber != null){
            // Again I add sku as key, not as value
            $arr[$product->StockNumber] = true;
        }
    }

    //Loop through the local products 
    $productsRemove = [];
    foreach ($localProducts->products as $localProduct) {
        // check with `isset` is faster
        if (isset($arr[$localProduct->sku])) {
            array_push($productsRemove, $localProduct);
        }
    }    
    return $productsRemove;
}