Find element of an array those contains only specific character set in PHP

Question

I need to find only the elements of an array that have a specific set of letters and any character before or after the set of letters.

I have arrays like these:

Answer 1

I am going to assume that you have already pre-filtered all strings to be either 4 or 5 characters long -- if not, you can uncomment my first filter function.

Inputs:

$findgroup=['eaten','enter','tend','sten','neat','dents','enet','netty','teeth','denet','teen','spent'];
$values=['e','n','t'];

Method:

//$findgroup=array_filter($findgroup,function($v){return strlen($v)==4 || strlen($v)==5;});
$findgroup=array_filter($findgroup,function($v)use($values){
    return
        sizeof(array_intersect(array_unique(str_split(substr($v,0,3))),$values))==3 ||
        sizeof(array_intersect(array_unique(str_split(substr($v,-3))),$values))==3;
});
var_export($findgroup);    
// omitted: neat, dents, teeth, teen

Output:

array (
  0 => 'eaten',
  1 => 'enter',
  2 => 'tend',
  3 => 'sten',
  6 => 'enet',
  7 => 'netty',
  9 => 'denet',
  11 => 'spent',
)