ctype_upper to check if all characters are upper case or not

$var="ABCD"; // All are Upper case character(s)
//$var="abCD"; // All or some are NOT Upper case character(s)
//$var="12AB"; // All or some are NOT Upper case character(s)
//$var="#%AB"; // All or some are NOT Upper case character(s)

if(ctype_upper($var)){
	echo "$var All are Upper case character(s)";
}else{ 
	echo " $var All or some are NOT Upper case character(s)";
}

output

ABCD All are Upper case character(s)

Syntax

ctype_upper($input_string);

Checking for presence of only upper case letters by using ctype_upper()
We can check a string to know if all characters present are in upper case letters or not.

Return value will be TRUE ( if all are Upper case chars ) or FALSE.

Here is the code using ctype_upper()

$string='ABCDEF';
if (ctype_upper($string)) {
echo " All characters are Upper  case only ";
}else{
echo " All or some characters are NOT Upper  case  ";
}

The output of above code will be

All characters are Upper case only

Presence of Blank space

This function checks for lower cases chars only so presence of any blank space will return as FALSE only.

$string='ABC DEF';

if (ctype_lower($string)) {
echo " All characters are Upper case only ";
}else{
echo "All or some characters are NOT Upper  case ";
}

Output will be

All or some characters are NOT Upper case

Presence of Special characters

Presence of Special characters will also return FALSE , only change the string part like this in above code.

$string='ABC)DEF';

Output will be

All or some characters are NOT Upper case

Examples multiple strings & ctype_upper()

$str = array("HELLO WORLD", "ABCDEF", "AB!CD","67");
foreach ($str as $val){
if (ctype_upper($val)){
 echo "<p class='text-success'>The string $val consists of Upper Case letters .</p>";
 } else {
 echo "<p class='text-danger'>The string $val does not consist of all Upper case letters.</p>";
}
}

Output is here

The string HELLO WORLD does not consist of all Upper case letters.
The string ABCDEF consists of Upper Case letters .
The string AB!CD does not consist of all Upper case letters.
The string 67 does not consist of all Upper case letters.

Check for only alphabetic characters by ctype_alpha() Check for all lower or upper Check for at least one lower case or upper case
ctype()

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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ctype_upper():Checking for all upper case chars

Presence of Blank space

Presence of Special characters

Examples multiple strings & ctype_upper()

Subhendu Mohapatra