Grouping similar items in an array

[londrum]

Hello. I'm hoping that someone with more brains than me can work this out...

I've got an array which looks something like this:

$fruits = array(

1 => 'Apple',

2 => 'Banana',

3 => 'Orange',

4 => 'Apple'

)

and what i need to do is loop through and find all the identical values, and combine their keys. so it would turn into this:

$fruits = array(

'1, 4' => 'Apple',

2 => Banana,

3 => Orange

)

whilst i can easily delete the duplicate values, i cant find a way to delete them and combine their keys with the original. any ideas?

[rainborick]

I always admire folks that can come up with a super-efficient algorithm for problems like this. I usually end up brute forcing it with something like:

$new_fruits = array();

 foreach ($fruits as $key => $value) {
 if (array_key_exists($value, $new_fruits)) {
 $new_fruits[$value] .= ",$key";
  } else {
 $new_fruits[$value] = $key;
 } // endif
 } // end foreach
 $fruits = array_flip($new_fruits);

(written on the fly and untested!)

[londrum]

cool, that looks like it might be good. let me try at work in the morning and let you know

[londrum]

...it works perfectly, thx rainborick