Remove value from array if value is a substring of another value

Question

Array
(
    [0] => tt0087523
    [1] => cehennem melekleri
    [3] => euer weg führt durch die hölle
    [5] => guerreiros selvagens
    [7] => jungel krigerne
    [9] => jungle fever
    [11] => jungle warriors
    [17] => jungle warriors euer weg führt durch die hölle
    [19] => la guerra de la coca
    [21] => les guerriers de la jungle
    [23] => los guerreros de la jungla
    [25] => the czar of brazil
    [27] => viidakkosoturit
)

How would I remove all values that are a substring of another value. For example remove index [3] as it is a substring of [17] and also [11] as that is also a substring of 17.

I am building a string for text search and wanted it to be as short as possible.

Update: re: comments :)

foreach ($array as $i => $value) {
    foreach ($array as $j => $search) {
        if ($i === $j) continue;
        if (false !== stripos($search, $value)) {
            unset($array[$i]);
        }
    }
}

We prefer questions like: I want to do this and got stuck here rather than: I want to do this tell me how. Anyway, as far as I know you would have to have to loop through every element and compare it to every other element. — Marty
– Marty, Commented Nov 4, 2013 at 0:30
@CrayonViolent Point taken! Just off the back of a bunch of other problem solving and was lost temporarily :) — user2856585
– user2856585, Commented Nov 4, 2013 at 0:40
@user2856585 bah.. seems you accepted an answer already :/ I posted my take anyways — CrayonViolent
– CrayonViolent, Commented Nov 4, 2013 at 1:07

CrayonViolent · Accepted Answer · 2013-11-04 01:31:18Z

4

How about...

array_walk($array, function(&$v,$k,&$a) {
  if(count(preg_grep('~'.preg_quote($v,'~').'~i',$a))>1)unset($a[$k]);
},&$array);

edit:

I tested this in php 5.3.22 and passing by reference to a function has been removed by 5.4 so as OP suggested, here is the 5.4+ alt:

array_walk($array, function (&$v, $k) use (&$array) { 
  if(count(preg_grep('~'.preg_quote($v,'~').'~i', $array))>1)unset($array[$k]); 
});

edited Nov 4, 2013 at 1:31

answered Nov 4, 2013 at 1:07

CrayonViolent

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8 Comments

user2856585 Over a year ago

As I accepted an answer that was the same as my own solution. This has to be the winner, two new functions for me to learn :) Thank you!

CrayonViolent Over a year ago

@user2856585 note that this is a case-insensitive comparison. If you want it to be case-sensitive, remove the i modifier in that preg_grep

user2856585 Over a year ago

Fatal error: Call-time pass-by-reference has been removed using PHP 5.5.5

CrayonViolent Over a year ago

oh snap.. i tested in 5.3.22

user2856585 Over a year ago

array_walk($array, function (&$v, $k) use (&$array) { if (count(preg_grep('~'.preg_quote($v).'~i', $array)) > 1) unset($array[$k]); });

|

Guilherme Soares · Accepted Answer · 2013-11-04 00:45:14Z

You can use two loop to check if string is substr:

$array = array(
"0" => "tt0087523",
"1" => "cehennem melekleri",
"3" => "euer weg führt durch die hölle",
"5" => "guerreiros selvagens",
"7" => "jungel krigerne",
"9" => "jungle fever",
"11" => "jungle warriors",
"17" => "jungle warriors euer weg führt durch die hölle",
"19" => "la guerra de la coca",
"21" => "les guerriers de la jungle",
"23" => "los guerreros de la jungla",
"25" => "the czar of brazil",
"27" => "viidakkosoturit");

foreach($array as $key => $value){
    foreach($array as $key2 => $value_to_compare){
        if($key2 == $key)
            continue;

        $pos = strpos($value_to_compare, $value);

        if($pos !== false){
            unset($array[$key]);
        }
    }
}

print_r($array);
/*

Array
(
    [0] => tt0087523
    [1] => cehennem melekleri
    [5] => guerreiros selvagens
    [7] => jungel krigerne
    [9] => jungle fever
    [17] => jungle warriors euer weg führt durch die hölle
    [19] => la guerra de la coca
    [21] => les guerriers de la jungle
    [23] => los guerreros de la jungla
    [25] => the czar of brazil
    [27] => viidakkosoturit
)

*/

user2778699 · Accepted Answer · 2014-08-09 14:17:55Z

0

Crayon's array_walk is a neat solution except for the unset() which changes the array index and causes the array_walk to skip a record, hence some duplicates can be left in there.

Instead of unset(), replace that value with an empty string and run array_filter to remove empty values after the walk.

array_walk($array, function (&$v, $k) use (&$array) { 
  if(count(preg_grep('~'.preg_quote($v,'~').'~i', $array))>1)unset($array[$k]); 
    $array[$i] = '';
});
$array = array_filter($array);

answered Aug 9, 2014 at 14:17

user2778699

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