How to put php infinite classification array

In Web development, various classification systems are widely used, and Infinitus classification is one of the common classification methods. Infinitus classification refers to a classification method that does not limit the number of classification levels in the classification system, so its array structure requires special processing.

php language is often used in web development. Let’s discuss the placement method of php infinite classification array.

1. Recursive method

The recursive method is the most commonly used method in PHP Infinitus classification array. It relies on recursive calls of functions to construct classified data.

The recursive method is written as follows:

/**
 * 无限极分类
 * @param array $data         分类数据
 * @param int $pid            父ID
 * @param int $level          层级数
 * @return array              分类数组
 */
function getTree($data, $pid = 0, $level = 0) {
    $tree = [];
    foreach ($data as $val) {
        if ($val['parent_id'] == $pid) {
            $val['level'] = $level;
            $val['children'] = getTree($data, $val['id'], $level + 1);
            $tree[] = $val;
        }
    }
    return $tree;
}

In the above code, the getTree function receives three parameters, namely the classification data $data, the parent ID $pid and the number of levels $level. The function first creates a $tree array, then iterates through the classification data, and if the parent ID of the current classification item is equal to $pid, it is added to the $tree array. Each classification item will add a level attribute, indicating the current level number. At the same time, the getTree function will call itself recursively, passing in the subcategory array as a parameter, so that the subcategory items can also be processed in the same way.

2. Loop method

The loop method is another processing method in PHP Infinitus classification array. It mainly realizes the construction of classified data through loop nesting.

The loop method is written as follows:

/**
 * 无限极分类
 * @param array $data         分类数据
 * @return array              分类数组
 */
function getTree($data) {
    $tree = [];
    $node = [];
    foreach ($data as $val) {
        $node[$val['id']] = $val;
    }
    foreach ($node as $key => &$val) {
        if (isset($node[$val['parent_id']])) {
            $node[$val['parent_id']]['children'][] = &$val;
        } else {
            $tree[] = &$val;
        }
    }
    return $tree;
}

In the above code, the getTree function receives a parameter $data, which represents classified data. The function first creates a $tree array and a $node array and puts the $data data into the $node array. Then, the foreach loop traverses the $node array. If the parent ID of the current category item is in the $node array, the current category item is added to the children subarray of the parent category item.

Since the elements in the $node array are stored according to the category ID, if the category item to be processed has not been traversed, it means that the category item is a top-level category, so the category item can be added directly $ tree array. The function finally returns the $tree array, which is an infinite categorical array.

Conclusion

The above are two methods of processing PHP infinite classification arrays. The recursive method is simpler and the loop method is more flexible. Since the recursive method uses recursive function calls, problems such as call stack overflow will occur when encountering extremely long or large amounts of data, while the loop method can better handle large amounts of data. During use, you can choose a method that suits you according to your actual development needs.

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