PHP infinite classification best practices-PHP Tutorial-php.cn

Infinite Classification

is a very common and necessary function, almost every project has it.
Application scenarios: drop-down lists, tree lists, etc.

Types of infinite classification

Front-end implementation (The front-end framework has generally been implemented, and it can be generated as long as the back-end transmits data to the front-end in the specified format)
Back-end Implementation(The following mainly talks about this kind of implementation)

Infinitely multiple implementations

The first type (recommended)

function infiniteSort($data, $showFName, $titleFName, $pidFName = 'pid', $idFName = 'id', $levelFName = 'level', $pid = 0, $level = 0)
{
    $tree = array();

    foreach ($data as $key => $value) {

        if ($value[$pidFName] == $pid) {
            $value[$levelFName] = $level;
            $value[$showFName] = str_repeat('  ', $level) . '|-' . $value[$titleFName];
            $tree[] = $value;
            unset($data[$key]);
            $tempArr = infiniteSort($data, $showFName, $titleFName, $pidFName, $idFName, $level, $value[$idFName], $level + 1);
            if(!empty($tempArr)){
                $tree = array_merge($tree, $tempArr);
            }
        }

    }

    return $tree;
}

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Note:
1, $data All data that has been sorted by asc
2, $showFName Display name Field name of the title (formatted)
3. $titleFName Field name of the title (unformatted)
4. $levelFName Level field name
5, $pidFName The field name of the parent id
6, $idFName The field name of the id

The second type (using reference variables)

/**
 * 无限级分类
 * @param Array $treeList //接受处理完成数据的数组
 * @param Array $data //数据库里获取的结果集
 * @param String $level //格式化层级字段名
 * @param Int $pid
 * @param Int $count //第几级分类
 */
function tree(&$treeList, &$data, $level, $show_name, $field_name, $field_pid = 'pid', $field_id = 'id', $pid = 0, $count = 0)
{
    foreach ($data as $key => $value) {

        if ($value[$field_pid] == $pid) {
            $value[$level] = $count;
            $value[$show_name] = str_repeat('    ',$count).'|-'.$value[$field_name];
            $treeList[] = $value;
            unset($data[$key]);
            tree($treeList, $data, $level, $show_name, $field_name,$field_pid, $field_id, $value[$field_id], $count+1);
        }

    }
}

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Note:
1, $data All data that has been sorted by asc
2 , the returned infinite list data is stored in $treeList

The third type (there are restrictions on using static variables: if a request is called twice to achieve 2 Infinite level classification will cause problems, so it is not recommended)

    public function getTree($list, $parent_id, $level=0) {
        //应该是静态的局部变量，这样才能保证，在递归调用时，所有
        //的getTree方法，操作的是一个Tree空间。
        static $tree = array();//保存找到的分类的数组
        //遍历所有分类，通过parent_id判断，哪些是我们正在查找的
        foreach($list as $row) {
            //判断当前所遍历的分类$row, 是否是当前需要查找的子分类
            if($row['pid'] == $parent_id) {
                //找到了一个分类
                //存起来，存哪?
                $row['level'] = $level;
                $tree[] = $row;
                //继续查找当前$row所代表的分类的子分类
                $this->getTree($list, $row['id'], $level+1);
            }
        }
        return $tree;
    }

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Note:
1, $list All data that has been sorted by asc

Unlimited classification

is a very common and necessary function, almost every project has it.
Application scenarios: drop-down lists, tree lists, etc.

Types of infinite classification

Front-end implementation (The front-end framework has generally been implemented, and it can be generated as long as the back-end transmits data to the front-end in the specified format)
Back-end Implementation(The following mainly talks about this kind of implementation)

Infinitely multiple implementations

The first type (recommended)

function infiniteSort($data, $showFName, $titleFName, $pidFName = 'pid', $idFName = 'id', $levelFName = 'level', $pid = 0, $level = 0)
{
    $tree = array();

    foreach ($data as $key => $value) {

        if ($value[$pidFName] == $pid) {
            $value[$levelFName] = $level;
            $value[$showFName] = str_repeat('  ', $level) . '|-' . $value[$titleFName];
            $tree[] = $value;
            unset($data[$key]);
            $tempArr = infiniteSort($data, $showFName, $titleFName, $pidFName, $idFName, $level, $value[$idFName], $level + 1);
            if(!empty($tempArr)){
                $tree = array_merge($tree, $tempArr);
            }
        }

    }

    return $tree;
}

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Note:
1, $data All data that has been sorted by asc
2,$ showFName Display the field name of the name (formatted)
3, $titleFName The field name of the title (unformatted)
4, $levelFName Hierarchical field name
5, $pidFName Field name of parent id
6, $idFName Field name of id

Second type (using reference variables)

/**
 * 无限级分类
 * @param Array $treeList //接受处理完成数据的数组
 * @param Array $data //数据库里获取的结果集
 * @param String $level //格式化层级字段名
 * @param Int $pid
 * @param Int $count //第几级分类
 */
function tree(&$treeList, &$data, $level, $show_name, $field_name, $field_pid = 'pid', $field_id = 'id', $pid = 0, $count = 0)
{
    foreach ($data as $key => $value) {

        if ($value[$field_pid] == $pid) {
            $value[$level] = $count;
            $value[$show_name] = str_repeat('    ',$count).'|-'.$value[$field_name];
            $treeList[] = $value;
            unset($data[$key]);
            tree($treeList, $data, $level, $show_name, $field_name,$field_pid, $field_id, $value[$field_id], $count+1);
        }

    }
}

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Note:
1, $data All data that has been sorted by asc
2. The returned infinite-level list data is stored in $treeList

The third type (there are restrictions on using static variables: if one request calls Implementing two infinite levels of classification twice will cause problems, so it is not recommended)

    public function getTree($list, $parent_id, $level=0) {
        //应该是静态的局部变量，这样才能保证，在递归调用时，所有
        //的getTree方法，操作的是一个Tree空间。
        static $tree = array();//保存找到的分类的数组
        //遍历所有分类，通过parent_id判断，哪些是我们正在查找的
        foreach($list as $row) {
            //判断当前所遍历的分类$row, 是否是当前需要查找的子分类
            if($row['pid'] == $parent_id) {
                //找到了一个分类
                //存起来，存哪?
                $row['level'] = $level;
                $tree[] = $row;
                //继续查找当前$row所代表的分类的子分类
                $this->getTree($list, $row['id'], $level+1);
            }
        }
        return $tree;
    }

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Note:
1, $list All data that has been sorted by asc

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