如果数组值等于x Ruby，则在数组中打印数组

Question

我是Ruby的新手，我试图通过编写一个简单的终端程序来练习一些技能，该程序可以在温哥华找到一个远足地点。 （虽然这可能不是最终编写程序的最佳方法，但我正在尝试使用此程序测试数组技能。）

我所做的是将5个远足点排列成二维阵列。 每个数组都包括远足的名称，位置，难度和持续时间。 我希望用户输入自己的偏好，然后打印出匹配的涨幅。

例如，如果用户输入6km，我想从<= 6km的数组中打印出远足名称。

因此，我只想打印以下代码，但前提是“＃{hikes [i] [0]}”中的[0] <= 6

    hikes.each_index{|i| puts "#{hikes[i][0]} " }

谢谢您的帮助！

到目前为止，这是我的代码：

    #Hiking Array: [Hike Name, Location, Difficulty, Length(km)] 

    hikes = 
    [["Admiralty Point", "Tri Cities", "Easy", 5],
    ["Habrich Ridge Trail", "Howe Sound", "Intermediate", 7],
    ["Aldergrove Regional Park", "Surrey",  "Easy", 5],
    ["Alice Lake", "Howe Sound", "Easy", 6],
    ["Ancient Cedars Trail", "Whistler", "Intermediate", 5]]


    puts "It's the weekend! Where should we go hiking?\n\n"
    puts "Here is the list of available hikes."
    puts "___________________________"

    hikes.each_index{|i| puts "#{hikes[i][0]} " }

    puts "\n"
    puts "How many kilometers do we want to hike?"
    kilometers = $stdin.gets.chomp

    puts "\n"
    puts "How hard do we want the hike to be, Easy or Intermediate?"
    difficulty = $stdin.gets.chomp

    puts "\n"
    puts "What area of town do we want to hike in:"
    puts "Tri Cities"
    puts "Howe Sound"
    puts "Surrey"
    puts "Whistler"
    area_of_town = $stdin.gets.chomp

    puts "\n"
    puts "Ok searching for awesome views that are #{kilometers}km, of #{difficulty} difficulty, and are in #{area_of_town}."

    hikes.each_index{|i| puts "#{hikes[i][2]}"}

Answer 1

也许

hikes.select {|arr| arr[3] <= 5}.each{|arr| puts arr[0]}

但我建议您使用哈希，以便您可以使用名称来寻找所需的属性。

hikes = [{'location'=>'Admirality', 'difficulty'=>5}, {'location'=>'Admirality', 'difficulty'=>10}, {'location'=>'Admirality', 'difficulty'=>15}]

hikes.select {|hsh| hsh["difficulty"] <= 10}

Answer 2

如果嵌套数组与所有3个条件都匹配，则只需使用“和”运算符&&从嵌套数组中打印名称，例如：

hikes.each do |h|
    puts h[0] if ( h[3] <= kilometers &&
                    h[2].downcase == difficulty.downcase && 
                    h[1].downcase == area_of_town.downcase )
end

• 我将所有字符串在匹配之前都转换为downcase ，以防万一用户输入与数组字符串不匹配（例如"Easy" vs "easy" ）
• 如果要打印匹配数组的所有详细信息， puts h.join(', ') puts h[0]更改为puts h.join(', ') 。

Answer 3

您可以考虑按以下步骤进行操作（在通过消除某些加长属性进行简化之后）：

hikes = 
  [["Admiralty Point", 5],
  ["Habrich Ridge Trail", 7],
  ["Aldergrove Regional Park", 5],
  ["Alice Lake", "Howe Sound", 6],
  ["Ancient Cedars Trail", 5]]

HIKES_BY_DISTANCE =
  hikes.each_with_object(Hash.new {|h,k| h[k] = []}) {|a,h| h[a.last] << a}
  #=> {5=>[["Admiralty Point", 5],
  #        ["Aldergrove Regional Park", 5],
  #        ["Ancient Cedars Trail", 5]],
  #    7=>[["Habrich Ridge Trail", 7]],
  #    6=>[["Alice Lake", "Howe Sound", 6]]} 

def select_hikes(length_range)
  HIKES_BY_DISTANCE.each_with_object([]) do |(k,v),a|
    a.concat(v) if length_range.cover?(k)
  end
end

select_hikes(4..5)
  #=> [["Admiralty Point", 5],
  #    ["Aldergrove Regional Park", 5],
  #    ["Ancient Cedars Trail", 5]] 
select_hikes(2..6)
  #=> [["Admiralty Point", 5],
  #    ["Aldergrove Regional Park", 5],
  #    ["Ancient Cedars Trail", 5],
  #    ["Alice Lake", "Howe Sound", 6]] 
select_hikes(4..7)
  #=> [["Admiralty Point", 5],
  #    ["Aldergrove Regional Park", 5],
  #    ["Ancient Cedars Trail", 5],
  #    ["Habrich Ridge Trail", 7],
  #    ["Alice Lake", "Howe Sound", 6]] 
select_hikes(6..9)
  #=> [["Habrich Ridge Trail", 7],
  #    ["Alice Lake", "Howe Sound", 6]] 
select_hikes(7..7)
  #=> [["Habrich Ridge Trail", 7]] 
select_hikes(1..2)
  #=> [] 
select_hikes(8..9)
  #=> []