RRList 
Inspired by RRDTool
Basically, you can add elements to a list, but the sizes remains constant over time.
If you add an element to to the list that is out of the range, moves the cursor forward and items at the lower indexes are lost.
For example with a list of size 5:
[1,2,3,4,5]
add 6
[2,3,4,5,6]
add 7
[3,4,5,6,7]
add 20
[nil,nil,nil,nil,20]
Install
gem install rrlist
or
gem 'rrlist'
or
git clone ...
rake install
Usage
require 'rrlist'Basic manipulation
rrlist = RRList::List.new :size => 10
rrlist.values #=> [nil, nil, nil, nil, nil, nil, nil, nil, nil, nil]
1.upto(100) { |n| rrlist.add(n) }
rrlist.values #=> [91, 92, 93, 94, 95, 96, 97, 98, 99, 100]
rrlist.min_index #=> 91
rrlist.min_index #=> 100
rrlist.get(93) #=> 93
rrlist.add(101)
rrlist.values #=> [92, 93, 94, 95, 96, 97, 98, 99, 100, 101]
rrlist.min_index #=> 92
rrlist.min_index #=> 101
rrlist.add("any object")
rrlist.values #=> [93, 94, 95, 96, 97, 98, 99, 100, 101, "any object"]
rrlist.min_index #=> 93
rrlist.min_index #=> 102
rrlist.add_at 105, "A"
rrlist.values #=> [96, 97, 98, 99, 100, 101, "any object", nil, nil, "A"]
rrlist.min_index #=> 96
rrlist.max_index #=> 105
rrlist.add_at 2000,"B"
rrlist.add_at 105, "A"
rrlist.values #=> [nil, nil, nil, nil, nil, nil, nil, nil, nil, "B"]
rrlist.min_index #=> 1991
rrlist.max_index #=> 2000Looping
rrlist = RRList::List.new :size => 10
1.upto(100) { |n| rrlist.add(n) }
rrlist.each { |value| ... }
rrlist.each_with_index { |value,index| puts "#{value} #{index}" }
# => 91 91
# => 92 92
....Ranges
A range of indexs grouped in the same position. For a renge of 3 for indexes 0,1,2 the value goes in position 1
rrlist = RRList::List.new :size => 10, :range => 3
rrlist.add_at 0, 0
rrlist.values #=> [0, nil, nil, nil, nil, nil, nil, nil, nil, nil]
rrlist.add_at 1, 1
rrlist.values #=> [1, nil, nil, nil, nil, nil, nil, nil, nil, nil]
rrlist.add_at 2, 2
rrlist.values #=> [2, nil, nil, nil, nil, nil, nil, nil, nil, nil]
rrlist.add_at 3, 3
rrlist.values #=> [2, 3, nil, nil, nil, nil, nil, nil, nil, nil]
rrlist.add_at 4, 4
rrlist.values #=> [2, 4, nil, nil, nil, nil, nil, nil, nil, nil]
rrlist.add_at 5, 5
rrlist.values #=> [2, 5, nil, nil, nil, nil, nil, nil, nil, nil]
rrlist = RRList::List.new :size => 10, :range => 5
0.upto(100) { |n| rrlist.add(n) }
rrlist.values #=> [59, 64, 69, 74, 79, 84, 89, 94, 99, 100]
rrlist.min_index #=> 55
rrlist.max_index #=> 100Functions
To sum all the values added to a range
rrlist = RRList::List.new :size => 10, :range => 5 do |index, old_value, new_value|
(old_value||0) + new_value
end
0.upto(100) { |n| rrlist.add(n) }
rrlist.values #=> [285, 310, 335, 360, 385, 410, 435, 460, 485, 100]
rrlist.min_index #=> 55
rrlist.max_index #=> 100Array API
rrlist = RRList::List.new :size => 10
rrlist.values #=> [nil, nil, nil, nil, nil, nil, nil, nil, nil, nil]
rrlist[1]="a"
rrlist.values #=> [nil, "a", nil, nil, nil, nil, nil, nil, nil, nil]
rrlist[1] #=> "a"
rrlist[2]="b"
rrlist.values #=> [nil, "a", "b", nil, nil, nil, nil, nil, nil, nil]
rrlist[2] #=> "b"
rrlist << "c"
rrlist.values #=> [nil, "a", "b", "c", nil, nil, nil, nil, nil, nil]
rrlist[3] #=> "c"License
MIT