How I can delete special characters?

Question

Hi there! Now I practice deleting characters such as:

input = input.gsub(/<\/?[^>]*>/, '')

and for special characters, example ☻ or ™:

input = input.gsub('&#', '')

this leaves only numbers, ok. But this only works if the user enters a special character as a code, like this:

™

My question: How I can delete special characters if the user enters a special character without code, like this:

™ ☻

Answer 1

You can match all the characters you want, and then join them together, like this:

original = "aøbæcå"
stripped = original.scan(/[a-zA-Z]/).to_s
puts stripped

which outputs "abc"

Answer 2

First of all, I think it might be easier to define what constitutes "correct input" and remove everything else. For example:

input = input.gsub(/[^0-9A-Za-z]/, '')

If that's not what you want (you want to support non-latin alphabets, etc.), then I think you should make a list of the glyphs you want to remove (like ™ or ☻), and remove them one-by-one, since it's hard to distinguish between a Chinese, Arabic, etc. character and a pictograph programmatically.

Finally, you might want to normalize your input by converting to or from HTML escape sequences.

Answer 3

If you just wanted ASCII characters, then you can use:

original = "aøbauhrhræoeuacå" 
cleaned = ""
original.each_byte { |x|  cleaned << x unless x > 127   }
cleaned   # => "abauhrhroeuac"