Delete duplicate words in array with sentences in PHP - php

Question

I have a string array with words and sentences included.
For example:
array("dog","cat","the dog is running","some other text","some","text")
And I want to remove duplicate words, leaving only unique words in it. I want to remove these words even in sentences.
The result should look like:
array("dog","cat","the is running","other","some","text")
I tried the array_unique function but it didn't work.

Answer 1

You can use the array_unique after loop with explode and array_push:
$res = [];
foreach($arr as $e) {
array_push($res, ...explode(" ", $e));
}
print_r(array_unique($res));
Reference:
array_push, explode, array-unique
Live example: 3v4l
If you want to keep the sentences use:
$arr = array("dog","cat","the dog is running","some other text","some","text");
// sort first to get the shortest sentence first
usort($arr, function ($a, $b) {return count(explode(" ", $a)) - count(explode(" ", $b)); });
$words = [];
foreach($arr as &$e) {
$res[] = trim(strtr($e, $words)); //get the word after swapping existing
foreach(explode(" ", $e) as $w)
$words[$w] =''; //add all new words to the swapping array with value of empty string
}

Answer 2

This solution is not pretty, but should get the job done and meet some of the edge cases at hand. I'm assuming that no more than one space separates words in a sentence string and that you want to preserve original ordering.
The approach is to walk the array twice, once to filter out duplicate single words, then once again to filter out duplicate words in sentences. This guarantees priority for single words. Finally, ksort the array (this is the ugly part from a time complexity standpoint: everything is O(max_len_sentence * n) up until now).
$arr = ["dog","cat","the dog is running","some other text","some","text"];
$seen = [];
$result = [];
foreach ($arr as $i => $e) {
if (preg_match("/^\w+$/", $e) &&
!array_key_exists($e, $seen)) {
$result[$i] = $e;
$seen[$e] = 1;
}
}
foreach ($arr as $i => $e) {
$words = explode(" ", $e);
if (count($words) > 1) {
$filtered = [];
foreach ($words as $word) {
if (!array_key_exists($word, $seen)) {
$seen[$word] = 0;
}
if (++$seen[$word] < 2) {
$filtered[]= $word;
}
}
if ($filtered) {
$result[$i] = implode($filtered, " ");
}
}
}
ksort($result);
$result = array_values($result);
print_r($result);
Output
Array
(
[0] => dog
[1] => cat
[2] => the is running
[3] => other
[4] => some
[5] => text
)