.upcase! makes if statement fail to work properly

Question

begin
puts "Enter selection:\n\n"
$main = gets.chomp

        if $main.upcase! == "A"
                    call_function_1
        elsif $main.upcase! == "B"
                    call_function_2
        end

end while $main != "~"

With the code as it is, entering A runs call_function_1, but entering B seems to be ignored.

The issue appears to be the .upcase! , as when I remove it, it works fine... why?

Answer 1

You should be using upcase, not upcase!. I would also use a case statement instead of the if block.

begin
  puts "Enter selection:\n\n"

  input = gets.chomp

  case input.upcase
  when 'A'
    call_function_1
  when 'B'
    call_function_2
  end

end while $main != "~"