php-regexHow to use PHP regex to match a hexadecimal?

Using PHP regex to match a hexadecimal is quite simple. The following example code block will match a hexadecimal string of any length:

$hexadecimal = preg_match('/^[0-9A-Fa-f]+$/', $string);

The output of the above code will be 1 if the string is a valid hexadecimal, and 0 if it is not.

Code explanation

• /^: This is the start of the regular expression.
• [0-9A-Fa-f]: This is the character class that matches any hexadecimal character.
• +: This is a quantifier that matches one or more of the preceding character class.
• $/: This is the end of the regular expression.

Helpful links

• PHP Regular Expressions
• Regular Expressions Tutorial

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