对foreach函数循环结果进行排序

Question

I have a MySQL query that gets the result of the entire MySQL database into a php array called $parents

then I have a foreach function loop that display result from that array

the function:

 function subtree($id, $parents) { 
 if (isset($parents[$id]))
 foreach ($parents[$id] as $child) 
 {
 subtree($child, $parents);
 }
 } 

I need to sort the array result of this function, or to get the result into a new_sub_array then sort it and display result

any way to modify the function to do what i need?

Answer 1

Change your condition

if (is_array($parents[$id]))

If Value is array then look for next sub tree

else

otherwise write value.

If you want to sort an array - just use one of this function at the beginning of subtree()

Good idea is to don't use recursion, instead of this you can use iteration and well prepared sql query instead of sorting in PHP ;)

Your function could look like this, I am not sure if I understand you, but it should be ok.

function subtree($parents) 
{
    if (is_array($parents))
    {
        sort($parents);
        foreach ($parents as $key => $value) 
        {
            subtree($value);
        }
    }
    else
    {
        echo $parents;
    }
} 

The $id argument is unnecessary.

Answer 2

You'd sort the values when you call them from the database. So if you sorted them in descending order of date, for example:

SELECT * FROM values WHERE :id=$id ORDER BY date DESC

Basically, ORDER BY is your friend. This helped me a lot.