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ctype_upper

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

ctype_upper — Check for uppercase character(s)

Description

ctype_upper(mixed $text): bool

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

Parameters

text

The tested string.

Note:

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.

Warning

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.

Examples

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

<?php
$strings = array('AKLWC139', 'LMNSDO', 'akwSKWsm');
foreach ($strings as $testcase) {
    if (ctype_upper($testcase)) {
        echo "The string $testcase consists of all uppercase letters.\n";
    } else {
        echo "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

© 1997–2025 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/function.ctype-upper.php