(PHP 7, PHP 8)
IntlChar::toupper — Make Unicode character uppercase
$codepoint): int|string|nullThe given character is mapped to its uppercase equivalent. If the character has no uppercase equivalent, the character itself is returned.
codepointThe int codepoint value (e.g. 0x2603 for U+2603 SNOWMAN), or the character encoded as a UTF-8 string (e.g. "\u{2603}")
Returns the Simple_Uppercase_Mapping of the code point, if any; otherwise the code point itself.
返回类型是 int，如果代码点作为 UTF-8 string 传递，则会返回 string 。失败时返回 null。
示例 #1 Testing different code points
<?php
var_dump(IntlChar::toupper("A"));
var_dump(IntlChar::toupper("a"));
var_dump(IntlChar::toupper("Φ"));
var_dump(IntlChar::toupper("φ"));
var_dump(IntlChar::toupper("1"));
var_dump(IntlChar::toupper(ord("A")));
var_dump(IntlChar::toupper(ord("a")));
?>以上示例会输出：
string(1) "A" string(1) "A" string(2) "Φ" string(2) "Φ" string(1) "1" int(65) int(65)