RRList

Docs

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

“by require ‘rrlist’

“

Basic manipulation

“by 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      #=> 2000

“

Looping

“by 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

“by 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  #=> 100

“

Functions

To sum all the values added to a range

“by 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  #=> 100

“

Array API

“by 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"

“