PHP function to determine uppercase and lowercase letters_PHP tutorial

Provide a simple example of the PHP function for judging uppercase and lowercase letters. It can find out how many uppercase letters and lowercase letters there are in a string. It is a very convenient and commonly used function. ​

Provide a simple example of the PHP tutorial to determine the uppercase and lowercase letters function. It can find out how many uppercase letters and how many lowercase letters a string has. It is a very convenient and commonly used function.

function checkcase($str){
If(preg_match('/^[a-z]+$/', $str)){
echo 'lowercase letters';
                 }elseif(preg_match('/^[a-z]+$/', $str)){
echo 'uppercase letters';
              }
}

Method 2

$str = 'a';
function checkcase1($str){
$str = ord($str);
If($str>64&&$str<91){
           echo 'uppercase letters';
         return;
}
If($str>96&&$str<123){
           echo 'lowercase letters';
         return;
}
echo 'Not a letter';
}
function checkcase2($str){
If(strtoupper($str)===$str){
           echo 'uppercase letters';
}else{
           echo 'lowercase letters';
}
}
echo checkcase1($str);
echo checkcase2($str);
?>

http://www.bkjia.com/PHPjc/445425.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/445425.htmlTechArticleProvides a simple example of PHP function to determine upper and lower case letters. It can find out how many uppercase letters there are in a string. How many lowercase letters are there in a letter? It is a very convenient and commonly used function. Mention...