Access variables programmatically by name in Ruby

What if you turn your problem around? Instead of trying to get names from variables, get the variables from the names:

["foo", "goo", "bar"].each { |param_name|  param = eval(param_name)  if param.class != Array    puts "#{param_name} wasn't an Array. It was a/an #{param.class}"    return "Error: #{param_name} wasn't an Array"  end  }

If there were a chance of one the variables not being defined at all (as opposed to not being an array), you would want to add "rescue nil" to the end of the "param = ..." line to keep the eval from throwing an exception...

You need to re-architect your solution. Even if you could do it (you can't), the question simply doesn't have a reasonable answer.

Imagine a get_name method.

a = 1get_name(a)

Everyone could probably agree this should return 'a'

b = aget_name(b)

Should it return 'b', or 'a', or an array containing both?

[b,a].each do |arg|  get_name(arg)end

Should it return 'arg', 'b', or 'a' ?

def do_stuff( arg )  get_name(arg)dodo_stuff(b)

Should it return 'arg', 'b', or 'a', or maybe the array of all of them? Even if it did return an array, what would the order be and how would I know how to interpret the results?

The answer to all of the questions above is "It depends on the particular thing I want at the time." I'm not sure how you could solve that problem for Ruby.

It seems you are trying to solve a problem that has a far easier solution..

Why not just store the data in a hash? If you do..

data_container = {'foo' => ['goo', 'baz']}

..it is then utterly trivial to get the 'foo' name.

That said, you've not given any context to the problem, so there may be a reason you can't do this..

[edit] After clarification, I see the issue, but I don't think this is the problem.. With [foo, bar, bla], it's equivalent like saying ['content 1', 'content 2', 'etc']. The actual variables name is (or rather, should be) utterly irrelevant. If the name of the variable is important, that is exactly why hashes exist.

The problem isn't with iterating over [foo, bar] etc, it's the fundamental problem with how the SOAP server is returing the data, and/or how you're trying to use it.

The solution, I would say, is to either make the SOAP server return hashes, or, since you know there is always going to be three elements, can you not do something like..

{"foo" => foo, "goo" => goo, "bar"=>bar}.each do |param_name, param|      if param.class != Array        puts "#{param_name} wasn't an Array. It was a/an #{param.class}"        puts "Error: #{param_name} wasn't an Array"      endend