# File activesupport/lib/active_support/core_ext/array/grouping.rb, line 62
def in_groups(number, fill_with = nil, &block)
# size.div number gives minor group size;
# size % number gives how many objects need extra accommodation;
# each group hold either division or division + 1 items.
division = size.div 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)
groups << last_group = slice(start, length)
last_group << fill_with if fill_with != false &&
modulo > 0 && length == division
start += length
end
if block_given?
groups.each(&block)
else
groups
end
end