Check if array element already partially exists inside of the array - php

Question

I have an array that looks like this:
[Amsterdam, Elderly people, Thousand students, Sixteen thousand students, Clean houses]
As you can see, there's an entry "thousand students" and an entry "sixteen thousand students". Is there a way that would let me filter out thousand students (and delete this entry), since it already partially exists?
However, just unsetting the element by hand won't work. The array is the result of an API, which means I won't know if there are partial duplicates or not.
thanks.
Edit: Expected result:
[Amsterdam, Elderly people, Sixteen thousand students, Clean houses]

Answer 1

So I'm trying to work out a slicker way without two loops, but this will do it:
foreach($array as $k => $a) {
foreach($array as $b) {
if(strtolower($a) !== strtolower($b) &&
(strpos(strtolower($b), strtolower($a)) !== false)) {
unset($array[$k]);
}
}
}
Loop the array and compare each value in lower case to each other value in lower case
If they are not equal and one is found within the other, use the key to remove the one found in the other
Maybe a little shorter:
foreach(array_map('strtolower', $array) as $k => $a) {
foreach(array_map('strtolower', $array) as $b) {
if($a !== $b && (strpos($b, $a) !== false)) {
unset($array[$k]);
}
}
}

Answer 2

Try this:
<?php
function custom_filter( $data ) {
$data_lc = array_map(function($value){
return strtolower($value);
}, $data);
foreach ($data_lc as $keyA => $valueA) {
foreach ($data_lc as $keyB => $valueB) {
if ( $keyA === $keyB ) {
continue;
}
if ( false !== strpos($valueA, $valueB) ) {
if ( strlen($valueA) <= strlen($valueB) ) {
unset($data[$keyA]);
} else {
unset($data[$keyB]);
}
}
}
}
return $data;
}
$array = ['Amsterdam', 'Elderly people', 'Thousand students', 'Sixteen thousand students', 'Clean houses'];
print_r( custom_filter( $array ) );

Answer 3

This should do the trick, however it'll only look for matches at the word level, and it's case sensitive.
<?php
$wordsList = [
'Amsterdam', 'Elderly people', 'Thousand students',
'Sixteen thousand students', 'Clean houses',
];
$lookup = array();
foreach ($wordsList as $k => $words) {
$phrase = '';
foreach (preg_split('`\s+`', $words, -1, PREG_SPLIT_NO_EMPTY) as $word) {
$phrase .= $word;
if (in_array($phrase, $words)) {
unset($wordsList[$k]);
break;
}
}
}