I have a product with optional variants like this:

SANDALS

1. Color: red, green, blue
2. Size: small, medium, large
3. Brand: brandX, brandY

every product variant is related to a set of selections. Example: if I select Color: red, Size: large, Brand: brandX, this will related to a product with an id of 820.

The way that the option tree should look like is this:

"optionTree": [
        [
            0,
            0,
            [
                820,
                0
            ]
        ],
        [
            0,
            [
                0,
                821
            ],
            [
                823,
                0
            ]
        ],
        [
            [
                824,
                825
            ],
            0,
            0
        ]
    ]

As can be seen, there are 3 product options to choose from, thus the depth of the tree is 3 deep. every level of the array relates to a product option. The first depth deals with Color, the second deals with Size, and the third with Brand (there could be a variable number of options not just 3). Thus, traversing the entire array to the bottom will result in a product id which matches all 3 choices. (the index of the choices relate to the indexes in the 'optionTree' array, also 0s are used to represent dead-ends)

Question: how do i order product selection variants in an array tree in such a way that they relate to their respective choices?

lets say i have an array of products which i would like to insert into an empty tree:

$products_to_add = [
            [
                "choices" => ['red', 'medium', 'brandX'],
                "product_id" => 820
            ],
            [
                "choices" => ['red', 'small', 'brandY'],
                "product_id" => 821
            ],
            [
                "choices" => ['green', 'small', 'brandX'],
                "product_id" => 822
            ],
            [
                "choices" => ['blue', 'large', 'brandY'],
                "product_id" => 823
            ],
        ]

How would i transform the array above into a coherent 'optionTree' like the one showed previously? (php or javascript is fine)

CodePudding user response：

You can use a loop in which you mutate the final tree as you go. Before starting it, you could prepare a helper structure which translates the name of a variant (like "red") to an index in the relevant (sub)array of the target structure. In PHP:

$props = [
    array_flip(["red", "green", "blue"]),
    array_flip(["small", "medium", "large"]),
    array_flip(["brandX", "brandY"])
];

Then in the main loop, you can benefit from the =& assignment for having a pointer walk through the result tree and adding null references (I prefer this than a 0) when arriving for the first time at a certain branch.

$optionTree = null;
foreach($products_to_add as $product) {
    $node =& $optionTree;
    foreach ($product["choices"] as $depth => $name) {
        if ($node == null) $node = array_fill(0, count($props[$depth]), null);
        $node =& $node[$props[$depth][$name]];
    }
    $node = $product["product_id"];
}
unset($node); // Safety, since it is a reference

After running this code, $optionTree will have the desired value.