Question

I’m writing a function that takes in a string ($skill), and a list of allowed characters in a regex.

Here is the requirements on the homework

1. Skill-name: required; can’t be too long; can contain spaces, hyphens, apostrophes (and of course alphanumeric characters), but no other characters
2. As part of this step, you must have a php function that takes in a string and a list of allowed characters (or, dis-allowed characters, or perhaps even a regular expression), and returns a an error message (if the string doesn’t match the requirement), or the empty string (if the string does match the requirement). Be sure to give a descriptive name to this function.

This is the code I have

function validate_skill($skill, $list) { 
if (preg_match('/['.$list.']/',$skill)) {
        echo "The skill contains a match.<br />";
    }else{
    echo "The skill does not contain a match.";
    }
}

I’m only receiving a blank page, and through commenting out the function, the page then works. Is this the proper way to have a variable be inside an expression?

Answer 1

You’ve either misunderstood your requirements, or you’re approaching this wrong. Here’s the simplified version of the requirements:

1. The function should have 2 arguments, the skill name, and some sort of validation string (in your case, list of allowed characters, a.k.a a whitelist). Got that ✔
2. The skill name shouldn’t be very long. This means you need to limit the length. ✘
3. By validating that the string matched the allowed character list, you need to make sure that it matched only those, and nothing else. Right now, you’re checking if any of the characters in the list is found. ✘
4. The function should return the error (or nothing), therefore, it should not echo anything by itself. ✘

You should be working on those points.

Also, on a different note, you have a syntax error. echo echo, should probably be else echo.