Invision Power Services > PHP: Cycling through all levels of an array?

Full Version: PHP: Cycling through all levels of an array?

Invision Power Services > Community Forums > Community Web Design and Coding

Mar 11 2005, 11:11 PM

This is something that has been baffling me for a looong time. How do you cycle through all levels of an array? For example, how to have this array:

CODE

array(
'test' => array(
'foo',
'bar'
),
'foobar' => array(
'this',
'that' => array(
'this',
'that'
)
)
)

Return this:

CODE

- test
-- foo
-- bar
- foobar
-- this
-- that
--- this
--- that

And continue working no matter how many levels are added? It's bound to be possible since IPB does it, with having unlimited subforums.

Thanks for any help.

Stephen

Mar 11 2005, 11:18 PM

CODE

function recursive_array($array) {
    static $indent = 0;
    $indent++;

    foreach ($array as $key => $var) {
        if (is_array($var)) {
            echo str_pad(" ", $indent + 1, "-", STR_PAD_LEFT) . $key ."<br />";
            recursive_array($var);
        }
        else {
            echo str_pad(" ", $indent + 1, "-", STR_PAD_LEFT) . $var . "<br />";
        }
    }
    $indent--;
}

Haven't tried that but it should work, or at least give you a running start

Rikki

Mar 11 2005, 11:20 PM

You need to use recursion; that is, a function that calls itself.

CODE

function doArrayThing($array, $currentprefix)
{
     foreach($array as $thing)
     {
           if(is_array($thing))
           {
                doArrayThing($thing, $currentprefix . "-");
            }
            else
             {
                  echo $currentprefix . $thing . "<br>";
             }
      }
}

doArrayThing($myarray, "-");

Mar 11 2005, 11:24 PM

I was convinced you couldn't do recursive functions in PHP. O__O
Stephen - It doesn't quite work, just returns:

CODE

foobarthisthisthat

[edit] I got it. This is the code:

CODE

<?php

$array = array(
'test' => array(
'foo',
'bar'
),
'foobar' => array(
'this',
'that' => array(
'this',
'that'
)
)
);

function doArrayThing($array, $currentprefix)
{
foreach($array as $key => $thing)
{
if(is_array($thing))
{
echo $currentprefix . $key . "<br />";
doArrayThing($thing, $currentprefix . "-");
}
else
{
echo $currentprefix . $thing . "<br />";
}
}
}

doArrayThing($array, "");

?>

Stephen

Mar 11 2005, 11:30 PM

take a look again, fixed it

Mar 11 2005, 11:41 PM

Just going to add another question onto this topic.
I'm attempting to write something that'll generate an array like I posted in the beginning from a MySQL select. Let's say the select returns this:

CODE

array(
'0' => array(
'name' => 'test',
'parent' => NULL
),
'1' => array(
'name' => 'foo',
'parent' => '0'
),
'2' => array(
'name' => 'bar',
'parent' => '0'
),
'3' => array(
'name' => 'foobar',
'parent' => NULL
),
'4' => array(
'name' => 'this',
'parent' => '3'
),
'5' => array(
'name' => 'that',
'parent' => '3'
),
'6' => array(
'name' => 'this',
'parent' => '5'
),
'7' => array(
'name' => 'that',
'parent' => '5'
)
);

How would I write a function to get that arranged into the array I first posted?

This is really hard to me. =_=

Rikki

Mar 12 2005, 12:36 AM

CODE

foreach($array as $id => $info)
{
      $main_array[ $info['parent'] ][] = $info;
}

That should do it though you'd probably want to add some other stuff to it (like checking for null and acting on it).

Mar 12 2005, 01:20 PM

I need to learn not asking questions when I'm tired. Can't believe it was that simple.

Thank you very much.

Actually, hmm.
That makes the key of the array item be the parent.

Also, something else goes wrong here:

CODE

<?php
$array = array(
'0' => array(
'name' => 'test',
'parent' => NULL
),
'1' => array(
'name' => 'foo',
'parent' => '0'
),
'2' => array(
'name' => 'bar',
'parent' => '0'
),
'3' => array(
'name' => 'foobar',
'parent' => NULL
),
'4' => array(
'name' => 'this',
'parent' => '3'
),
'5' => array(
'name' => 'that',
'parent' => '3'
),
'6' => array(
'name' => 'this',
'parent' => '5'
),
'7' => array(
'name' => 'that',
'parent' => '5'
)
);

$arranged = array();

foreach($array as $key => $value)
{
if(is_null($value['parent']))
{
$arranged[$value['parent']] = array();
}

$arranged[$value['parent']][$value['name']] = $value;
}

function arrange($array, $currentprefix)
{
foreach($array as $key => $thing)
{
if(is_array($thing))
{
echo $currentprefix . $key . "<br />";
arrange($thing, $currentprefix . "-");
}
else
{
echo $currentprefix . $thing . "<br />";
}
}
}

arrange($arranged, "-");

?>

Returning:

CODE

-
--foobar
---foobar
---
-0
--foo
---foo
---0
--bar
---bar
---0
-3
--this
---this
---3
--that
---that
---3
-5
--this
---this
---5
--that
---that
---5

Mar 13 2005, 12:08 PM

Anyone?

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