Class: Array

Inherits:
Object show all
Defined in:
lib/picolena/templates/lib/core_exts.rb

Instance Method Summary collapse

Instance Method Details

#in_transposed_slices(n) ⇒ Object

Returns a partition of n arrays. Transposition is used to avoid getting arrays that are too different.

>> (0..17).to_a.in_transposed_slices(5)
=> [[0, 5, 10, 15], [1, 6, 11, 16], [2, 7, 12, 17], [3, 8, 13], [4, 9, 14]]

while

>> (0..17).enum_slice(5).to_a
=> [[0, 1, 2, 3, 4], [5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17]]

If some folders contain big files and some others contain small ones, every indexing thread will get some of both!



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# File 'lib/picolena/templates/lib/core_exts.rb', line 42

def in_transposed_slices(n)
  # no need to compute anything if n==1
  return [self] if n==1
  # Array#transpose would raise if Array is not a square array of arrays.
  i=n-self.size%n
  # Adds nils so that size is a multiple of n,
  # cuts array in slices of size n,
  # transposes to get n slices,
  # and removes added nils.
  (self+[nil]*i).enum_slice(n).to_a.transpose.collect{|e| e.compact}
end