The ctype_xdigit() function in PHP check for character(s) representing a hexadecimal digit. It returns TRUE if every character in text is a hexadecimal 'digit', that is a decimal digit or a character from [A-Fa-f], FALSE otherwise.
Syntax
ctype_xdigit(str)
Parameters
str − The tested string
Return
The ctype_xdigit() function returns TRUE if every character in text is a hexadecimal 'digit', that is a decimal digit or a character from [A-Fa-f], FALSE otherwise.
Example
The following is an example −
<?php $str = array('ABCD', 'AB768768ff'); foreach ($str as $a) { if (ctype_xdigit($a)) { echo "$a has all hexadecimal digits. \n"; } else { echo "$a does not have all hexadecimal digits. \n"; } } ?>
Output
ABCD has all hexadecimal digits. AB768768ff has all hexadecimal digits.