How do I convert an integer to a list and vice versa in Oz?

Question

How do I convert an integer to a list and back in Oz? I need to take a number like 321 and reverse it into 123.

The Reverse function in Oz only works on lists so I want to convert 321 to [3 2 1], reverse it, and convert [1 2 3] back to 123. Can this be done in Oz?

score 1 · Accepted Answer · edited Jan 01 '10 at 18:52

Disclaimer: I didn't actually know Oz until 5 minutes ago and only read the examples at Wikipedia, so the following may be riddled with errors. It should however give you a good idea on how to approach the problem. (Making the function tail-recursive is left as an exercise to the reader).

Update: The following version is tested and works.

local
  % turns 123 into [3,2,1]
  fun {Listify N}
    if N == 0 then nil
    else (N mod 10) | {Listify (N div 10)}
    end
  end

  % turns [1,2,3] into 321
  fun {Unlistify L}
    case
      L of nil then 0
      [] H|T then H + 10 * {Unlistify T}
    end
  end
in
  % Turns 123 into 321
  {Browse {Unlistify {Reverse {Listify 123}}}}
end

Very clever. I actually figured out how to reverse the digits of the number mathematically using mod and div and so no longer need to convert the numbers to a list in order to Reverse them. Thanks. — el diablo, Sep 27 '09 at 12:03

score 1 · Answer 2 · answered Jan 01 '10 at 17:56

1

This should do the trick more succintly:

{Show {StringToInt {Reverse {IntToString 123}}}}

Cheers

answered Jan 01 '10 at 17:56

JFT

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How do I convert an integer to a list and vice versa in Oz?

2 Answers2