3 ms·

so this is horribly non-idiomatic ruby, but it was fun p ->(*_) { _.reduce({}, :merge).tap { |_| return "<none>" if _.empty? }.keys.uniq.map(&:to_s).sort

so this is horribly non-idiomatic ruby, but it was fun p ->(*_) { _.reduce({}, :merge).tap { |_| return "<none>" if _.empty? }.keys.uniq.map(&:to_s).sort.join(", ") }.({c:3,d:4,b:2}, {f:5,e:4,a:1}) p ->(*_) { _.reduce({}, :merge).tap { |_| return "<none>" if _.empty? }.keys.uniq.map(&:to_s).sort.join(", ") }.({}, {}) # "a, b, c, d, e, f" # "<none>" edit: a little bit better. func = ->(*_) { return "<none>" if _.all?(&:empty?) _.flat_map(&:keys).uniq.map(&:to_s).sort.join(", ") } func.({c:3,d:4,b:2}, {f:5,e:4,a:1}) #=> "a, b, c, d, e, f" func.({}, {}) #=> "<none>" https://gist.github.com/66b45e765a2aa6a97143 https://gist.github.com/66b45e765a2aa6a97143

griffindy 14y ago
slightly more idiomatic, though perhaps not quite as clear as the clojure: def unique_keys(*hashes) result = {} hashes.each do |hash| result.merge! hash end return result.keys.map(&:to_s).sort.join(', ') unless result.empty? '<none>' end https://gist.github.com/4695388 https://gist.github.com/4695388
- danneu 14y ago
  I think accumulating an initialized variable in an imperative #each loop is decidedly unidiomatic, just something we tend to do until we really embrace things like #map, #partition, #select, #reduce, etc. (And what a glorious day that is!) I reckon what makes his first example somewhat unidiomatic is the arbitrary lambda and the use & inner return from the #taps block. His updated example is just good ol tacit Ruby. But then again the amount of times I see an #each block with inner logic used instead of a simple point-free one-liner in Ruby really just proves your point.
markov_twain 14y ago
well, I hate to beat a dead horse, but here's a one-liner (ruby): (map1.keys | map2.keys).map(&:to_s).sort.join(", ").instance_eval { empty? ? "<none>" : self }
- Luyt 14y ago
  My one-liner: a = {"fred": 4, "wilma": 8} b = {"t-shirt": 6, "fred": 0} print ", ".join(sorted(set(a).union(b))) or "<none>"

griffindy 14y ago

slightly more idiomatic, though perhaps not quite as clear as the clojure: def unique_keys(*hashes) result = {} hashes.each do |hash| result.merge! hash end return result.keys.map(&:to_s).sort.join(', ') unless result.empty? '<none>' end https://gist.github.com/4695388 https://gist.github.com/4695388

danneu 14y ago
I think accumulating an initialized variable in an imperative #each loop is decidedly unidiomatic, just something we tend to do until we really embrace things like #map, #partition, #select, #reduce, etc. (And what a glorious day that is!) I reckon what makes his first example somewhat unidiomatic is the arbitrary lambda and the use & inner return from the #taps block. His updated example is just good ol tacit Ruby. But then again the amount of times I see an #each block with inner logic used instead of a simple point-free one-liner in Ruby really just proves your point.

markov_twain 14y ago

well, I hate to beat a dead horse, but here's a one-liner (ruby): (map1.keys | map2.keys).map(&:to_s).sort.join(", ").instance_eval { empty? ? "<none>" : self }

Luyt 14y ago
My one-liner: a = {"fred": 4, "wilma": 8} b = {"t-shirt": 6, "fred": 0} print ", ".join(sorted(set(a).union(b))) or "<none>"