Floadting down from the sky (day 2) [SLiSW]

#it's getting really hard :o

#read and write a file with and without blocks

#method with blocks
filename = 'text.txt'
#write
File.open(filename,'w') {|file| file.write('ola ate logo')}
#read
File.open(filename,'r') {|file| puts file.read}


#method without blocks
filename = 'text.txt'
#write
file = File.open(filename,'w')
file.write('ola')
file.close
#read
file = File.open(filename,'r')
puts file.read
file.close


#can I translate hash to array? And array to hash?

#hash to array
array = []
hash = { "a"=>["a", "b", "c"], "b"=>["b", "c"] }
hash.each_key {|p| array.push(hash[p])}
#array to hash
array = [["a", "b", "c"], ["b", "c"]]
hash = Hash[*array]


#can I iterate through a hash ?
hash.each_value {|p| puts "-> #{p}"}


##DO
#Exercise 1
#
a = ['1','2','3','4','5','6','7','8','9','10','11','12','13','14','15','16']
#
a.each {|p| puts "-> #{p}"}
#
a.each_slice(4) {|p| puts "-> #{p}"}

#Exercise 2
#Well, it's a little  more complicated, so I need to make an example first and then implement in the tree
#So, based on this
hs = {"grandpa" => {"dad" => {"child1" => {}, "child2" => {}}, "uncle" => {"child3" => {}, "child4" => {}}}}
def readAll(tree = {})
    puts "tree-> #{tree}"
    nome = tree.keys[0]
    child = tree[nome].collect {|i,m| readAll(i=>m)}
end

readAll(hs)
#I updated the tree
class Tree
  attr_accessor :children, :node_name

  def initialize(tree={})
    @node_name = tree.keys[0]
    @children = tree[node_name].collect {|i,m| Tree.new(i=>m)}
  end

  def visit_all(&block)
    visit &block
    children.each {|c| c.visit_all &block}
  end

  def visit(&block)
    block.call self
  end

end

ruby_tree = Tree.new( {"grandpa" => {"dad" => {"child1" => {}, "child2" => {}}, "uncle" => {"child3" => {}, "child4" => {}}}} )


puts "visiting entire tree"
ruby_tree.visit_all {|node| puts node.node_name}


#Exercise 3
#the file text.txt contains
ola ate logo
ja sei
ainda nao sei
#and the code is
File.open('text.txt','r').each_with_index {|l,p| puts "-> #{l},#{p}" if l=~/sei(.*)/ }
#you can also use readlines or each_line insted of each_with_index but you will not get the index of line