Question

I have an array that’s stored like this:

[0] => Array
    (
        [id] => 1
        [cat_name] => c1
    )

[1] => Array
    (
        [id] => 2
        [cat_name] => c2
        [copii] => Array
            (
                [0] => Array
                    (
                        [id] => 5
                        [cat_name] => c21
                    )

                [1] => Array
                    (
                        [id] => 6
                        [cat_name] => c22
                    )

            )

    )

[2] => Array
    (
        [id] => 3
        [cat_name] => c3
        [copii] => Array
            (
                [0] => Array
                    (
                        [id] => 7
                        [cat_name] => c31
                        [copii] => Array
                            (
                                [0] => Array
                                    (
                                        [id] => 9
                                        [cat_name] => c311
                                    )

                            )

                    )

                [1] => Array
                    (
                        [id] => 8
                        [cat_name] => c32
                    )

            )

    )

I’m trying to find an easier way of finding a route to a certain ID.
Now I’m using foreach to iterate through all possible arrays and finding the route.

Example:

id = 1:
     route[0][id]=1,route[0][cat_name]=c1
id = 5:
    route[0][id]=2,route[0][cat_name]=c2
    route[1][id]=5,route[1][cat_name]=c21
id = 9:
    route[0][id]=3,route[0][cat_name]=c3
    route[1][id]=7,route[1][cat_name]=c31
    route[2][id]=9,route[2][cat_name]=c311

If my question makes no sense, I blame it on the hours spent trying to find a nice solution to it…

Answer 1

In lieu of posting a bunch of code, I’d suggest you read up on recursion if you don’t know about it. PHP isn’t too great at recursion, but it’s really your only option.

Basically you’d call a function that takes the array, id to find, and a string/array representing the path. Initially call that with a blank string or empty array for the latter parameter.

In the function you would do this:

• Run a foreach through the top level of $array
• If you find the $id you’re looking for, return the $path.
• If one of the array values is a sub array, add the current ID node and call the function again with that – something like $foundPath = findPath( $array, $id, $path ).
• If $foundPath returns something, then you’ve got your path and can return.
• If it didn’t find anything ($foundPath is false or null as below), leave it and move on to the next iteration of the loop.
• At the end of the loop, if you haven’t found anything, return false or null.

Hope that helps!