Regex to check alphanumeric string in ruby

Question

I am trying to validate strings in ruby. Any string which contains spaces,under scores or any special char should fail validation. The valid string should contain only chars a-zA-Z0-9 My code looks like.

def validate(string)
    regex ="/[^a-zA-Z0-9]$/
    if(string =~ regex)
        return "true"
    else
        return "false"
end

I am getting error: TypeError: type mismatch: String given.

Can anyone please let me know what is the correct way of doing this?

Answer 1

def alpha_numeric?(char)  
 
   if((char =~ /[[:alpha:]]) || (char =~ [[:digits:]]))
      true
   else
      false
   end

end

OR

def alpha_numeric?(char)  
 
   if(char =~ /[[:alnum:]])
      true
   else
      false
   end

end

We are using regular expressions that match letters & digits:

The above [[:alpha:]] ,[[:digit:]] and [[:alnum:]] are POSIX bracket expressions, and they have the advantage of matching Unicode characters in their category. Hope this helps.

checkout the link below for more options: Ruby: How to find out if a character is a letter or a digit?