Module: ActiveSupport::CoreExtensions::Array::Grouping

Included in:
Array
Defined in:
lib/support/active_support_lite/array/grouping.rb

Overview

:nodoc:all

Instance Method Summary (collapse)

Instance Method Details

- (Object) in_groups(number, fill_with = nil)

Splits or iterates over the array in number of groups, padding any remaining slots with fill_with unless it is false.

%w(1 2 3 4 5 6 7 8 9 10).in_groups(3) {|group| p group}
["1", "2", "3", "4"]
["5", "6", "7", nil]
["8", "9", "10", nil]

%w(1 2 3 4 5 6 7).in_groups(3, ' ') {|group| p group}
["1", "2", "3"]
["4", "5", " "]
["6", "7", " "]

%w(1 2 3 4 5 6 7).in_groups(3, false) {|group| p group}
["1", "2", "3"]
["4", "5"]
["6", "7"]

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# File 'lib/support/active_support_lite/array/grouping.rb', line 61

def in_groups(number, fill_with = nil)
  # size / number gives minor group size;
  # size % number gives how many objects need extra accomodation;
  # each group hold either division or division + 1 items.
  division = size / number
  modulo = size % number

  # create a new array avoiding dup
  groups = []
  start = 0

  number.times do |index|
    length = division + (modulo > 0 && modulo > index ? 1 : 0)
    padding = fill_with != false &&
      modulo > 0 && length == division ? 1 : 0
    groups << slice(start, length).concat([fill_with] * padding)
    start += length
  end

  if block_given?
    groups.each{|g| yield(g) }
  else
    groups
  end
end

- (Object) in_groups_of(number, fill_with = nil)

Splits or iterates over the array in groups of size number, padding any remaining slots with fill_with unless it is false.

%w(1 2 3 4 5 6 7).in_groups_of(3) {|group| p group}
["1", "2", "3"]
["4", "5", "6"]
["7", nil, nil]

%w(1 2 3).in_groups_of(2, '&nbsp;') {|group| p group}
["1", "2"]
["3", "&nbsp;"]

%w(1 2 3).in_groups_of(2, false) {|group| p group}
["1", "2"]
["3"]

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# File 'lib/support/active_support_lite/array/grouping.rb', line 23

def in_groups_of(number, fill_with = nil)
  if fill_with == false
    collection = self
  else
    # size % number gives how many extra we have;
    # subtracting from number gives how many to add;
    # modulo number ensures we don't add group of just fill.
    padding = (number - size % number) % number
    collection = dup.concat([fill_with] * padding)
  end

  if block_given?
    collection.each_slice(number) { |slice| yield(slice) }
  else
    returning [] do |groups|
      collection.each_slice(number) { |group| groups << group }
    end
  end
end

- (Object) split(value = nil)

Divides the array into one or more subarrays based on a delimiting value or the result of an optional block.

[1, 2, 3, 4, 5].split(3)                # => [[1, 2], [4, 5]]
(1..10).to_a.split { |i| i % 3 == 0 }   # => [[1, 2], [4, 5], [7, 8], [10]]

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# File 'lib/support/active_support_lite/array/grouping.rb', line 93

def split(value = nil)
  using_block = block_given?

  inject([[]]) do |results, element|
    if (using_block && yield(element)) || (value == element)
      results << []
    else
      results.last << element
    end

    results
  end
end