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December 19, 2015 18:09
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Recursively flatten an array. First uses Array#each, second uses no iteration. Both only use one arg.
(First attempt I posted actually called my first method... so it was undoubtedly incorrect as far as no iteration goes. This one's right though.)
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| # recursive but with Array#each | |
| def flatten(array) | |
| return [array] unless array.is_a?(Array) | |
| result = [] | |
| array.each do |x| | |
| result += flatten(x) | |
| end | |
| result | |
| end | |
| flatten ["bananas", [1,2,3], ["apple", "cheese", [100, 20]], [true], [4.0, 7, 32]] # => ["bananas", 1, 2, 3, "apple", "cheese", 100, 20, true, 4.0, 7, 32] | |
| flatten ["Washed Out", "Nujabes",[34,[54,67,87],67],["Pliney","Lagunitas"],[false],[23,1990,5]] # => ["Washed Out", "Nujabes", 34, 54, 67, 87, 67, "Pliney", "Lagunitas", false, 23, 1990, 5] | |
| # 1. No iteration inside the method (inject, each, map, etc. not allowed) | |
| # 2. No other arguments besides the input array | |
| def flatten_recur(array) | |
| return array if array == [] | |
| return [array] unless array.is_a?(Array) | |
| flatten_recur(array.shift) + flatten_recur(array) | |
| end | |
| flatten_recur ["Washed Out", "Nujabes",[34,[54,67,87],67],["Pliney","Lagunitas"],[false],[23,1990,5]] # => ["Washed Out", "Nujabes", 34, 54, 67, 87, 67, "Pliney", "Lagunitas", false, 23, 1990, 5] | |
| flatten_recur ["bananas", [1,2,3], ["apple", "cheese", [100, 20]], [true], [4.0, 7, 32]] # => ["bananas", 1, 2, 3, "apple", "cheese", 100, 20, true, 4.0, 7, 32] |
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