Remove all non-alphabetical, non-numerical characters from a string?

Question

If I wanted to remove things like: .!,'"^-# from an array of strings, how would I go about this while retaining all alphabetical and numeric characters.

Allowed alphabetical characters should also include letters with diacritical marks including à or ç.

Answer 1

You should use a regex with the correct character property. In this case, you can invert the Alnum class (Alphabetic and numeric character):

"◊¡ Marc-André !◊".gsub(/\p{^Alnum}/, '') # => "MarcAndré"

For more complex cases, say you wanted also punctuation, you can also build a set of acceptable characters like:

"◊¡ Marc-André !◊".gsub(/[^\p{Alnum}\p{Punct}]/, '') # => "¡MarcAndré!"

For all character properties, you can refer to the doc.

Answer 2

string.gsub(/[^[:alnum:]]/, "")

Answer 3

The following will work for an array:

z = ['asfdå', 'b12398!', 'c98347']
z.each { |s| s.gsub! /[^[:alnum:]]/, '' }
puts z.inspect

I borrowed Jeremy's suggested regex.

Answer 4

You might consider a regular expression.

http://www.regular-expressions.info/ruby.html

I'm assuming that you're using ruby since you tagged that in your post. You could go through the array, put it through a test using a regexp, and if it passes remove/keep it based on the regexp you use.

A regexp you might use might go something like this:

[^.!,^-#]

That will tell you if its not one of the characters inside the brackets. However, I suggest that you look up regular expressions, you might find a better solution once you know their syntax and usage.