From: Marnen Laibow-Koser <marnen@...>
Date: 2009-11-23T23:05:34+09:00
Subject: Re: More on psuedo arrays; Better way?

Ralph Shnelvar wrote:
> Newbie here:
> 
> Consider:
> 
> 
> 
> N_X_METHODS = 20
> 
> class X
>   20.times do |i|
>     define_method "x%02d=" % i do |arg|
>       # the puts, below, is just a placeholder for a more complicated 
> method
>       puts "Hi " + i.to_s + arg.to_s
>     end
>   end
> end
> 
> 
> m = Array.new(N_X_METHODS) do |i|
>   ("x%02d=" % i).to_sym
> end
> 
> p m
> 
> 
> 10.times do |i|
>   x = X.new
> 
>   # select a random method
>   x.method(m[rand(i % N_X_METHODS)]).call(i)
> end
> 
> 
> 
> 
> 
> 
> Let's focus on the line
>         x.method(m[rand(i % N_X_METHODS)]).call(i)
> 
> 
> Is there a better way to do this?  

x.send("x#{rand(i % N_X_METHODS)]".to_sym))

You don't need m at all.

> Is there a more Ruby-ish way to do
> anything else in the code, above?

Yes: use operators to make X look like a real array.

class X
  def []=(i, arg)
    puts "Hi " + i.to_s + arg.to_s
  end
end

N_X_METHODS = 20

10.times do |i|
  x = X.new # should this be outside the loop?
  x[rand(i % N_X_METHODS)] = i
end

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
-- 
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