Question

Lets say I have a file called foo.txt encoded in utf8:

aoeu  
qjkx
ñpyf

And I want to get an array that contains all the lines in that file (one line per index) that have the letters aoeuñpyf, and only the lines with these letters.

I wrote the following code (also encoded as utf8):

$allowed_letters=array("a","o","e","u","ñ","p","y","f");

$lines=array();
$f=fopen("foo.txt","r");
while(!feof($f)){
    $line=fgets($f);
    foreach(preg_split("//",$line,-1,PREG_SPLIT_NO_EMPTY) as $letter){
        if(!in_array($letter,$allowed_letters)){
            $line="";
        }
    }
    if($line!=""){
        $lines[]=$line;
    }
}
fclose($f);

However, after that, the $lines array just has the aoeu line in it.
This seems to be because somehow, the “ñ” in $allowed_letters is not the same as the “ñ” in foo.txt.
Also if I print a “ñ” of the file, a question mark appears, but if I print it like this print "ñ";, it works.
How can I make it work?

Answer 1

If you are running Windows, the OS does not save files in UTF-8, but in cp1251 (or something…) by default you need to save the file in that format explicitly or run each line in utf8_encode() before performing your check. I.e.:

$line=utf8_encode(fgets($f));

If you are sure that the file is UTF-8 encoded, is your PHP file also UTF-8 encoded?

If everything is UTF-8, then this is what you need :

foreach(preg_split("//u",$line,-1,PREG_SPLIT_NO_EMPTY) as $letter){
   // ...
}

(append u for unicode chars)

However, let me suggest a yet faster way to perform your check :

$allowed_letters=array("a","o","e","u","ñ","p","y","f");

$lines=array();
$f=fopen("foo.txt","r");
while(!feof($f)){
    $line=fgets($f);

    $line = str_split(rtrim($line));
    if (count(array_intersect($line, $allowed_letters)) == count($line)) {
            $lines[] = $line;
    }
}
fclose($f);

(add space chars to allow space characters as well, and remove the rtrim($line))