vendor/rails/activesupport/lib/active_support/core_ext/array/grouping.rb

   1 require 'enumerator'
   2
   3 module ActiveSupport #:nodoc:
   4   module CoreExtensions #:nodoc:
   5     module Array #:nodoc:
   6       module Grouping
   7         # Splits or iterates over the array in groups of size +number+,
   8         # padding any remaining slots with +fill_with+ unless it is +false+.
   9         #
  10         #   %w(1 2 3 4 5 6 7).in_groups_of(3) {|group| p group}
  11         #   ["1", "2", "3"]
  12         #   ["4", "5", "6"]
  13         #   ["7", nil, nil]
  14         #
  15         #   %w(1 2 3).in_groups_of(2, '&nbsp;') {|group| p group}
  16         #   ["1", "2"]
  17         #   ["3", "&nbsp;"]
  18         #
  19         #   %w(1 2 3).in_groups_of(2, false) {|group| p group}
  20         #   ["1", "2"]
  21         #   ["3"]
  22         def in_groups_of(number, fill_with = nil)
  23           if fill_with == false
  24             collection = self
  25           else
  26             # size % number gives how many extra we have;
  27             # subtracting from number gives how many to add;
  28             # modulo number ensures we don't add group of just fill.
  29             padding = (number - size % number) % number
  30             collection = dup.concat([fill_with] * padding)
  31           end
  32
  33           if block_given?
  34             collection.each_slice(number) { |slice| yield(slice) }
  35           else
  36             returning [] do |groups|
  37               collection.each_slice(number) { |group| groups << group }
  38             end
  39           end
  40         end
  41
  42         # Splits or iterates over the array in +number+ of groups, padding any
  43         # remaining slots with +fill_with+ unless it is +false+.
  44         #
  45         #   %w(1 2 3 4 5 6 7 8 9 10).in_groups(3) {|group| p group}
  46         #   ["1", "2", "3", "4"]
  47         #   ["5", "6", "7", nil]
  48         #   ["8", "9", "10", nil]
  49         #
  50         #   %w(1 2 3 4 5 6 7).in_groups(3, '&nbsp;') {|group| p group}
  51         #   ["1", "2", "3"]
  52         #   ["4", "5", "&nbsp;"]
  53         #   ["6", "7", "&nbsp;"]
  54         #
  55         #   %w(1 2 3 4 5 6 7).in_groups(3, false) {|group| p group}
  56         #   ["1", "2", "3"]
  57         #   ["4", "5"]
  58         #   ["6", "7"]
  59         def in_groups(number, fill_with = nil)
  60           # size / number gives minor group size;
  61           # size % number gives how many objects need extra accomodation;
  62           # each group hold either division or division + 1 items.
  63           division = size / number
  64           modulo = size % number
  65
  66           # create a new array avoiding dup
  67           groups = []
  68           start = 0
  69
  70           number.times do |index|
  71             length = division + (modulo > 0 && modulo > index ? 1 : 0)
  72             padding = fill_with != false &&
  73               modulo > 0 && length == division ? 1 : 0
  74             groups << slice(start, length).concat([fill_with] * padding)
  75             start += length
  76           end
  77
  78           if block_given?
  79             groups.each{|g| yield(g) }
  80           else
  81             groups
  82           end
  83         end
  84
  85         # Divides the array into one or more subarrays based on a delimiting +value+
  86         # or the result of an optional block.
  87         #
  88         #   [1, 2, 3, 4, 5].split(3)                # => [[1, 2], [4, 5]]
  89         #   (1..10).to_a.split { |i| i % 3 == 0 }   # => [[1, 2], [4, 5], [7, 8], [10]]
  90         def split(value = nil)
  91           using_block = block_given?
  92
  93           inject([[]]) do |results, element|
  94             if (using_block && yield(element)) || (value == element)
  95               results << []
  96             else
  97               results.last << element
  98             end
  99
 100             results
 101           end
 102         end
 103       end
 104     end
 105   end
 106 end