Iteration 2

Additional Methods - insert and prepend

Now we have nodes and a LinkedList class that manages the list. Next step is to add the insert and prepend methods.

prepend will add nodes to the beginning of the list.

insert will insert one or more elements at a given position in the list. It takes two parameters, the first one is the position at which to insert nodes, the second parameter is the string of data to be inserted.

Expected behavior:

pry(main)> require "./lib/linked_list"
#=> true

pry(main)> require "./lib/node"
#=> true

pry(main)> list = LinkedList.new
#=> #<LinkedList:0x000000010d670c88 @head=nil>

pry(main)> list.append("plop")

pry(main)> list.to_string
#=> "plop"

pry(main)> list.append("suu")

pry(main)> list.to_string
# "plop suu"

pry(main)> list.prepend("dop")

pry(main)> list.to_string
#=> "dop plop suu"

pry(main)> list.count
#=> 3

pry(main)> list.insert(1, "woo")

pry(main)> list.to_string
#=> "dop woo plop suu"

Additional Methods - find, pop, includes?

Perfect, we are almost there! Next is to add find, pop and includes? methods.

find takes two parameters, the first indicates the first position to return and the second parameter specifies how many elements to return.

includes? gives back true or false whether the supplied value is in the list.

pop removes the last element from the list and returns it.

Expected behavior:

....
pry(main)> list.to_string
#=> "deep woo shi shu blop"

pry(main)> list.find(2, 1)
#=> "shi" 

pry(main)> list.find(1, 3)
#=> "woo shi shu"

pry(main)> list.includes?("deep")
#=> true

pry(main)> list.includes?("dep")
#=> false

pry(main)> list.pop
#=> "blop"

pry(main)> list.pop
#=> "shu"

pry(main)> list.to_string
#=> "deep woo shi"