random_insertion.rb

# method for inserting items into an Array without overlapping or nesting them

a = (1..10).to_a
  # [1,2,3,4,5,6,7,8,9,10]
where = (10.times.collect {rand(10)}).sort {|a,b| b <=> a}
  # e.g., [9, 9, 8, 8, 7, 5, 4, 3, 3, 0]
where.each {|position| a.insert(position,["foo","bar"]).flatten!}
a
  # ["foo", "bar", 1, 2, 3, "foo", "bar", "foo", "bar", 4, "foo", "bar", 5, "foo", "bar", 6, 7, "foo", "bar", 8, "foo", "bar", "foo", "bar", 9, "foo", "bar", "foo", "bar", 10]