Problem with string

[Anon]

I have a string compund of many sentences. I want to replace all char. of sentences in lowercase and the first char in uppercase. Example:
"heLLo WorLD. this IS a TEST. hello yoU"
to
"Hello world. This is a test. Hello you"

[Anon]

$str = "heLLo WorLD. this IS a TEST. hello yoU";
$str = strtolower( $str );
$str_arr = explode( ". ", $str );
for($i=0;$i<sizeof($str_arr);$i++){
$str_arr[$i] = ucfirst( $str_arr[$i] );
}
$str = implode( ". ", $str_arr );
unset( $str_arr );

Or something like that.......