Determining duplicate letter counts between an array of strings - php

Question

I have an array of strings of random letters, and I need to know which letters are consistent between the array members. The count of the letters are important.
My method right now is loop through the array, doing a split, then looping through the spitted string to count the occurrences of each letter, then update the array with letter => count
Then do an array_reduce that creates a new array of members who only occur in all arrays. But, it's not working.
<?
$a[] = "emaijuqqrauw";
$a[] = "aaeggimqruuz";
$a[] = "aabimqrtuuzw";
$a[] = "aacikmqruuxz";
$a[] = "aacikmqruuxz";
$a[] = "aaciimqruuxy";
foreach($a as $b){
$n = str_split($b, 1);
foreach($n as $z){
$arr[$z] = substr_count($b, $z);
}
ksort($arr);
$array[] = $arr;
unset($arr);
}
$n = array_reduce($array, function($result, $item){
if($result === null){
return $item;
}else{
foreach($item as $key => $val){
if(isset($result[$key])){
$new[$key] = $val;
}
}
return $new;
}
});
foreach($n as $key => $val){
echo str_repeat($key, $val);
}
This returns aaiimqruu - which is kinda right, but there's only 2 i's in the last element of the array. There's only one i in the rest. I'm not sure how to break that down farther and get it to return aaimqruu- which I'll then pop into a SQL query to find a matching word, aquarium

Answer 1

There's array_intersect(), which is most likely what you'd want. Given your $a array, you'd do something like:
$a = array(.... your array...);
$cnt = count($a);
for($i = 0; $i < $cnt; $i++) {
$a[$i] = explode('', $a[$i]); // split each string into array of letters
}
$common = $a[0]; // save the first element
for($i = 1; $i < $cnt; $i++) {
$common = array_intersect($common, $a[$i]);
}
var_dump($common);

Answer 2

How about you do it this way? Finds out the occurrence of an item throughout the array.
function findDuplicate($string, $array) {
$count = 0;
foreach($array as $item) {
$pieces = str_split($item);
$pcount= array_count_values($pieces);
if(isset($pcount[$string])) {
$count += $pcount[$string];
}
}
return $count;
}
echo findDuplicate("a",$a);
Tested :)
Gives 12, using your array, which is correct.
Update
My solution above already had your answer
$pieces = str_split($item);
$pcount= array_count_values($pieces);
//$pcount contains, every count like [a] => 2

Answer 3

Seems like array_reduce is the best function for what this purpose, however I just didn't think of adding a conditional to give me the desired effect.
$new[$key] = ($result[$key] > $val) ? $val : $result[$key];
to replace
$new[$key] = $val;
did the trick.