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Challenges

Comments on Make my number a set

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Make my number a set

+7
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Natural to set

(set meaning an unordered collection with no duplicates, though answers may use and output lists instead)

Recently I was brainstorming what a language with only (arbitrarily nested) sets would be like. A number is represented with a set of that many elements. The elements need to be different, which leads to this definition:

Definition

  • The set representation of $0$ is the empty set.
  • The set representation of any other integer $n$ is the set of the set representations of all positive integers less than $n$, including zero.
  • Negative, complex, or rational numbers do not need to be handled.
  • Your full program or function is to convert from a positive integer to a set or list.

Examples

0 {}
1 {{}}
2 {{}, {{}}}
3 {{}, {{}}, {{}, {{}}}}
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Ruby, 27 bytes

->n{x=[];n.times{x<<x*1};x}

->n{                      }  # lambda taking n
    x=[];                    # set x to empty array
         n.times{      };    # repeat n times
                 x<<x*1      # append x with a copy of itself       
                         x   # return x

Try it online!

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1 comment thread

alternative 27 bytes: `o=->n{(0...n).map{|x|o[x]}}` (3 comments)
alternative 27 bytes: `o=->n{(0...n).map{|x|o[x]}}`
Wezl‭ wrote over 3 years ago

alternative 27 bytes: o=->n{(0...n).map{|x|o[x]}}

Wezl‭ wrote over 3 years ago

21 bytes: o=->n{(0...n).map &o}

snail_‭ wrote over 3 years ago

Feel free to submit your own answer, since this approach is different enough from my own. I only feel good about taking small golf improvements.