(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
ctype_upper — 检测大写字符
示例 #1 ctype_upper() 示例（使用当前默认语言环境）
<?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";
}
}
?>以上示例会输出：
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.