Introduction to the use of recursive function return values in PHP (ecshop unlimited classification)

Introduction to the use of recursive function return values in PHP (ecshop unlimited classification)_PHP tutorial

WBOY

Release： 2016-07-13 16:56:19

Original

709 people have browsed it

An introduction to the problem of returning values of recursive functions in PHP using ecshop infinite classification as an example.

When doing product category indexing in the secondary development of ecshop, the top-level category id must be obtained based on the category id. The first reaction was to use recursion, so I wrote the recursive function as follows:

if ($res[0]['parent_id'] > 0)
                                  {
               getCatTopId($res[0]['parent_id']);
         }
         else
                                  {
              return $res[0]['cat_id'];
         }
}
else
{
Return 1;
}
}

The code is as follows

代码如下

复制代码

function getCatTopId($cat_id)
{
    if ($cat_id)
    {
        $res = Array();
        $sql = 'SELECT cat_id, parent_id'
             . ' FROM ' . $GLOBALS['ecs']->table('category')
             . ' WHERE cat_id = ' . $cat_id . ' AND is_show = 1';

$res = $GLOBALS['db']->getAll($sql);

        if ($res[0]['parent_id'] > 0)
        {
            getCatTopId($res[0]['parent_id']);
        }
        else
        {
            return $res[0]['cat_id'];
        }
    }
    else
    {
        return 1;
    }
}

Copy code

代码如下

复制代码

function getCatTopId($cat_id)
{
    if ($cat_id)
    {
        $res = Array();

        $sql = 'SELECT cat_id, parent_id'
             . ' FROM ' . $GLOBALS['ecs']->table('category')
             . ' WHERE cat_id = ' . $cat_id . ' AND is_show = 1';

$res = $GLOBALS['db']->getAll($sql);

        if ($res[0]['parent_id'] > 0)
        {
            return getCatTopId($res[0]['parent_id']); // 修改处，多写个 return ，让函数返回值
        }
        else
        {
            return $res[0]['cat_id'];
        }    }
    else
    {
        return 1;
    }
}

function getCatTopId($cat_id)
{
If ($cat_id)
{
$res = Array();
$sql = 'SELECT cat_id, parent_id'
. ' FROM ' . $GLOBALS['ecs']->table('category')
. .

$res = $GLOBALS['db']->getAll($sql);

A test program, but no return value is obtained? After checking for a long time, no error was found. It seemed that the circuit in the brain was broken. When I asked the Water God (a kind-hearted netizen) today, he helped me answer it, and the modification is as follows:

The code is as follows

Copy code