编程打卡：来玩玩Ruby语言吧2.1！

我们前面实现了一个有趣的树类Tree，但它不具有简洁的用户接口，来设置一棵新树，为它写一个初始化方法，接受散列表和数组嵌套的结构。写好之后，你可以这样设置新树：{'grandpa' => { 'dad' => {'child 1' => {}, 'child 2' => {} }, 'uncle' => {'child 3' => {}, 'child 4' => {} } } }。

代码实现

class Tree
    attr_accessor :children, :node_name
    def initialize (tree)
        tree.each do
            |name,children|
            @children = children.map{|name,children| Tree.new(name => children)}
            @node_name = name
        end
    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({"Ruby" => {"Tim" => {"Dick" => {}},"Doge" => {"Wong" => {"Steve" => {}}}}})

ruby_tree.visit_all {|node| puts node.node_name}

运行结果

Ruby
Tim
Dick
Doge
Wong
Steve

写一个简单的grep程序,把文件中出现某词组的行打印出来,并且显示行号

代码实现

lineNumber = 1
targetWord = ARGV.shift
ARGF.each do
    |s|
    puts "#{lineNumber}: #{s}" if s.include? targetWord
    lineNumber += 1
end

运行结果

ruby main.rb Japanese hello123.txt
176:     Japanese: 私はガラスを食べられます。それは私を傷つけません。