Question

I have a list of words in which some are composed words, in example

• palanca
• plato
• platopalanca

I need to remove “plato” and “palanca” and let only “platopalanca”.
Used array_unique to remove duplicates, but those composed words are tricky…

Should I sort the list by word length and compare one by one?
A regular expression is the answer?

update: The list of words is much bigger and mixed, not only related words

update 2: I can safely implode the array into a string.

update 3: I’m trying to avoid doing this as if this was a bobble sort. there must be a more effective way of doing this

Well, I think that a buble-sort like approach is the only possible one 🙁
I don’t like it, but it’s what i have…
Any better approach?

function sortByLengthDesc($a,$b){
return strlen($a)-strlen($b);
}

usort($words,'sortByLengthDesc');
$count = count($words);
for($i=0;$i<=$count;$i++) {
    for($j=$i+1;$j<$count;$j++) {
        if(strstr($words[$j], $words[$i]) ){
            $delete[]=$i;
        }
    }
}
foreach($delete as $i) {
    unset($words[$i]);
}

update 5: Sorry all. I’m A moron. Jonathan Swift make me realize I was asking the wrong question.
Given x words which START the same, I need to remove the shortests ones.

• “hot, dog, stand, hotdogstand” should become “dog, stand, hotdogstand”
• “car, pet, carpet” should become “pet, carpet”
• “palanca, plato, platopalanca” should become “palanca, platopalanca”
• “platoother, other” should be untouchedm they both start different

Answer 1

I think you need to define the problem a little more, so that we can give a solid answer. Here are some pathological lists. Which items should get removed?:

• hot, dog, hotdogstand.
• hot, dog, stand, hotdogstand
• hot, dogs, stand, hotdogstand

SOME CODE

This code should be more efficient than the one you have:

$words = array('hatstand','hat','stand','hot','dog','cat','hotdogstand','catbasket');

$count = count($words);

for ($i=0; $i<=$count; $i++) {
    if (isset($words[$i])) {
        $len_i = strlen($words[$i]);
        for ($j=$i+1; $j<$count; $j++) {
            if (isset($words[$j])) {
                $len_j = strlen($words[$j]);

                if ($len_i<=$len_j) {
                    if (substr($words[$j],0,$len_i)==$words[$i]) {
                        unset($words[$i]);  
                    }
                } else {
                    if (substr($words[$i],0,$len_j)==$words[$j]) {
                        unset($words[$j]);
                    }
                }
            }
        }
    }
}

foreach ($words as $word) {
    echo "$word<br>";
}

You could optimise this by storing word lengths in an array before the loops.