(PHP 7, PHP 8)
IntlChar::isxdigit — Check if code point is a hexadecimal digit
Determines whether the specified code point is a hexadecimal digit.
true for characters with general category "Nd" (decimal digit numbers) as
well as Latin letters a-f and A-F in both ASCII and Fullwidth ASCII.
(That is, for letters with code points 0041..0046, 0061..0066, FF21..FF26, FF41..FF46.)
This is equivalent to IntlChar::digit($codepoint, 16) >= 0.
示例 #1 Testing different code points
<?php
var_dump(IntlChar::isxdigit("A"));
var_dump(IntlChar::isxdigit("1"));
var_dump(IntlChar::isxdigit("\u{2603}"));
?>以上示例会输出：
bool(true) bool(true) bool(false)
注意:
In order to narrow the definition of hexadecimal digits to only ASCII characters use:
<?php
$isASCIIHexadecimal = IntlChar::ord($codepoint) <= 0x7F && IntlChar::isxdigit($codepoint);
?>