Question

I want to check a string to allow only a-z A-Z 0-9 . / ? & but I’m unsure how exactly to use preg_match().

If you could also explain what each part of the code is I’d appreciate it! (ie why do you add /^ and how to you add a /)

Thanks

Answer 1

Here it is:

$input = 'Hello...?World';
$regex = '~^[a-z0-9&./?]+$~i';

if (preg_match($regex, $input)) {
  echo "yeah!";
}

You can build your own character classes and validate strings this way.

Explanation:

~
^                        # string start
[                        # start character class 
  a-z                    # letters from a to z
  0-9                    # digits from 0 to 9
  &./?                   # &,.,/ and ? chars
]                        # end character class
+                        # repeat one or more time
$                        # string end
~ix