(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

ctype_upperCheck for uppercase character(s)


ctype_upper(mixed $text): bool

Checks if all of the characters in the provided string, text, are uppercase characters.



The tested string.


If an int between -128 and 255 inclusive is provided, it is interpreted as the ASCII value of a single character (negative values have 256 added in order to allow characters in the Extended ASCII range). Any other integer is interpreted as a string containing the decimal digits of the integer.


As of PHP 8.1.0, passing a non-string argument is deprecated. In the future, the argument will be interpreted as a string instead of an ASCII codepoint. Depending on the intended behavior, the argument should either be cast to string or an explicit call to chr() should be made.

Return Values

Returns true if every character in text is an uppercase letter in the current locale. When called with an empty string the result will always be false.


Example #1 A ctype_upper() example (using the default locale)

= array('AKLWC139', 'LMNSDO', 'akwSKWsm');
foreach (
$strings as $testcase) {
if (
ctype_upper($testcase)) {
"The string $testcase consists of all uppercase letters.\n";
} else {
"The string $testcase does not consist of all uppercase letters.\n";

The above example will output:

The string AKLWC139 does not consist of all uppercase letters.
The string LMNSDO consists of all uppercase letters.
The string akwSKWsm does not consist of all uppercase letters.

See Also

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User Contributed Notes 2 notes

chris at theothernews dot co dot nz
10 years ago
Underscores in the string will result in false, so you have to remove them first.
8 years ago
// after screwing around with function.ctype-upper
// I found this simple solution

if (strtolower($string) != $string)// its so simple!
echo "uppercase letters found in $string";

source: http://stackoverflow.com/questions/4426327/how-to-detect-if-string-contains-1-uppercase-letter-in-php
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