在PHP中不使用RegEx计算大写和小写字母[关闭]

Question

How do I count Uppercase and Lowercase letters and numbers in a string without using regular expressions?

Answer 1

$string    = "HelLo wOrlD";
$lowerCase = strtolower($string);
$upperCase = strtoupper($string);

$lowerDiff = similar_text($string, $lowerCase);
$upperDiff = similar_text($string, $upperCase);

echo "Capital:" . (strlen($string) - $lowerDiff); // 4
echo "<br>";
echo "Lowercase:" . (strlen($string) - $upperDiff); // 6