ruby - Nil class error for array sorting

Question

When I tried to shorten an array, I get an error like this:

in `sort_by': undefined method `<=>' for nil:NilClass (NoMethodError)
@@secarr=@@secarr.sort_by{ |hotelname, location, cuisine, price| hotelname }

Please explain because I am a newbie to ruby.

Answer 1

Your code is correct in the respect that hotelname is being compared among the elements in @@secarr. The error message you encountered means that hotelname is (sometimes) nil, and cannot be compared. Comparison can only be done on classes that include Enumerable module. The solution is to, assuming hotelname is normally a string, put to_s after hotelname.

@@secarr = @@secarr.sort_by{|hotelname, location, cuisine, price| hotelname.to_s}