PHP validate string lightweight - php

Question

I want to find the most lightweight solution to validate a string as a letter or number + ?. Eg: a? or 1? etc.

Answer 1

if (preg_match('/^[a-z0-9]\?$/', $str)) {
// yup, it's a letter or number + ?
}

Answer 2

slighty faster than regular expression is function:
// return true or false
function validate($str) {
$str0 = ord($str[0]);
return(
(
($str0 >= 97 && $str0 <= 122) or
($str0 >= 48 && $str0 <= 57)
) &&
(
$str[1] == '?'
)
);
}

Answer 3

Some time ago, i've written a lightweight-validation class. Maybe you can use it.
For example:
$oValidator = new Validator();
$oValidator->isValid('a', 'alpha_numeric|max_length[1]'); //true
$oValidator->isValid('1', 'alpha_numeric|max_length[1]'); //true
$oValidator->isValid('ab', 'alpha_numeric|max_length[1]'); //false
$oValidator->isValid('1337', 'alpha_numeric|max_length[1]'); //false
Example:
http://sklueh.de/2012/09/lightweight-validator-in-php/
github:
https://github.com/sklueh/Lightweight-PHP-Validator

Answer 4

OK This is the fastest way
$allowed_char = Array();
for($i=ord('a');$i<=ord('z');$i++) $allowed_char[chr($i)] = true;
for($i=ord('0');$i<=ord('9');$i++) $allowed_char[chr($i)] = true;
function validate($str) {
global $allowed_char;
return $allowed_char[$str[0]] && $str[1] == '?' && !isset($str[2]);
}
Regexp = 2.0147299766541s
This solution = 1.6041090488434s
So it's 20% faster than Regexp solution :)