Class: Array
- Defined in:
- lib/shenanigans/array/caret.rb,
lib/shenanigans/array/zip_with.rb,
lib/shenanigans/array/reductions.rb,
lib/shenanigans/array/random_subarray.rb
Instance Method Summary collapse
-
#^(other) ⇒ Object
Returns an array containing elements exclusive between two arrays.
-
#random_subarray(n = 1) ⇒ Object
Generates random subarrays.
-
#reductions(*args, &block) ⇒ Object
Similar to
reduce
/inject
, but also returns intermediate values. -
#zip_with(other, op = nil) ⇒ Object
Zip
self
withother
, combining the elements with the provided block or symbol.
Instance Method Details
#^(other) ⇒ Object
Returns an array containing elements exclusive between two arrays.
[1, 2, 3] ^ [1, 2, 4]
#=> [3, 4]
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# File 'lib/shenanigans/array/caret.rb', line 5 def ^(other) (self - other) | (other - self) end |
#random_subarray(n = 1) ⇒ Object
Generates random subarrays. Uses random numbers and bit-fiddling to assure performant uniform distributions even for large arrays.
a = *1..5
a.(3)
#=> [[1, 3, 5], [2, 4], [1, 3, 4, 5]]
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# File 'lib/shenanigans/array/random_subarray.rb', line 9 def (n=1) raise ArgumentError, "negative argument" if n < 0 (1..n).map do r = rand(2**self.size) self.select.with_index { |_, i| r[i] == 1 } end end |
#reductions(*args, &block) ⇒ Object
Similar to reduce
/inject
, but also returns intermediate values. Has the same interface as reduce
/inject
, so an initial value, an oprator or both can be supplied. This method may eventually be moved to the Enumerable
module.
a = [*1..4]
a.reductions(:+)
#=> 10
a.reductions(50, :+)
#=> 60
%w(a b c).reductions { |s1, s2| s1+s2 }
#=> ["a", "ab", "abc"]
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# File 'lib/shenanigans/array/reductions.rb', line 11 def reductions(*args, &block) arr = dup if args.size == 1 Symbol === (arg = args.first) ? op = arg : initial = arg else initial, op, _ = args end raise ArgumentError, "Need an operator or block" unless op || block initial ||= arr.shift arr.inject([initial, [initial]]) do |(acc, result), el| val = op ? acc.send(op, el) : yield(acc, el) [val, result << val] end.last end |
#zip_with(other, op = nil) ⇒ Object
Zip self
with other
, combining the elements with the provided block or symbol. The resulting array will be as long as the shorter of the two arrays.
[1,2,3].zip_with([6,5,4], :+)
#=> [7, 7, 7]
%w(a b).zip_with(%w(c d), :+)
#=> ["ac", "bd"]
For more complex combinations, a block can be provided:
[1,2,3].zip_with([6,5,4]) { |a,b| 3*a+2*b }
#=> [15, 16, 17]
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# File 'lib/shenanigans/array/zip_with.rb', line 16 def zip_with(other, op=nil) return [] if self.empty? || other.empty? clipped = self[0..other.length-1] zipped = clipped.zip(other) if op zipped.map { |a, b| a.send(op, b) } else zipped.map { |a, b| yield(a, b) } end end |