From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2012-09-28T17:09:08+09:00
Subject: Re: calcaulation with unknown numbers of numbers and options fail

On Fri, Sep 28, 2012 at 9:40 AM, Roelof Wobben <rwobben@hotmail.com> wrote:
> Hello,
>
> I have this script:
>
> def calculate (options , *numbers)
>   options << "add" if options.empty?
>   numbers.inject(0) { |sum, number| sum + number } if options == "add"
>   numbers.inject() { |sum, number| sum - number } if options == "subtract"
> end
>
> But now I see this output in Rubymonks :
>
> defaults to addtion when no option is specifiedNoMethodErrorundefined method
> `empty?' for 4:Fixnuminvoking calculate(4, 5, add: true) returns
> 9NoMethodErrorundefined method `empty?' for 4:Fixnuminvoking calculate(-10,
> 2, 3, add: true) returns -5NoMethodErrorundefined method `empty?' for
> -10:Fixnuminvoking calculate(0, 0, 0, 0, add: true) returns
> 0NoMethodErrorundefined method `empty?' for 0:Fixnum
>
> I think the problem is that I cannot take care that the right values are in
> the right variable.
>
>
> Anyone a tip how to solve this ?

The options hash is the first parameter to your function, so pass it
as the first parameter:

calculate({:add => true}, 4,5)

and also, you shouldn't check options == "add", but options[:add] ==
true or just options[:add]

Jesus.