Question

我主要关注＆＃34; 4＆＃34;根据案例next_choice声明。我想在库存哈希中挑出键值对，然后将其与sell_inventory哈希值进行比较，如果库存值大于sell_inventory中的值，则从库存值中减去两者的差值。完成所有这些后，我想清除sell_inventory哈希值，这样如果再次选择选项4，我可以重复这个过程。我无法弄清楚如何做到这一点，因为当涉及到红宝石哈希时，我会变成绿色。

inventory = {}
sell_inventory = {}

p "Press enter to continue to program."
choice = gets.chomp.downcase

until choice.empty?
choice = gets.chomp.downcase
p "That is not a valid choice, please press enter to start."
end

while true
case choice
    when ""
        p "1. Show items in inventory"
        p "2. Add new item to inventory"
        p "3. Remove item from inventory"
        p "4. Sell items"
        p "5. Buy items"
        next_choice = gets.chomp.downcase
            case next_choice
                when "1" 
                    p "#{inventory}"
                when "2"
                      p "What item would you like to store?"
                      item = gets.chomp
                      if inventory.has_key?(item)
                      p "You already have that item in storage."
                    else
                      inventory[item]
                      p "How many of the items would like to store?"
                      amount = gets.chomp.to_i
                      inventory[item] = amount
                      p "Items added to inventory."
                    end

                    when "3"
                      p "What item would you like to remove from inventory?"
                      item_to_remove = gets.chomp.to_i
                      if inventory.include?(item_to_remove)
                        inventory.delete_if {|item, id| item == 
                        item_to_remove}
                      else
                         p "That item is not in stock."
                      end
                    when "4"
                      p "What item would you like to sell?"
                      items_to_sell = gets.chomp
                      sell_inventory[items_to_sell]
                      p "How many of that item would you like to sell?"
                      amount_to_sell = gets.chomp.to_i
                      sell_inventory[items_to_sell] = amount_to_sell
            end
    when "exit"
        break
    end
end

Answer 1

我不确定sell_inventory哈希的用途。如果您只是希望用户输入一个项目，然后从库存中减去该项目，则可以执行此操作。

示例，说库存设置如下：

inventory = { 'pencil' => 3 }
items_to_sell = 'pencil' # user entered this
amount_to_sell = 1 # user entered this
inventory[items_to_sell] -= amount_to_sell if amount_to_sell <= inventory[items_to_sell]

库存现在包含数量为2的铅笔：

inventory = { 'pencil' => 2 }

在上面的示例中，有一个数量为3的铅笔。变量items_to_sell设置为铅笔（可能通过用户输入），并且amount_to_sell变量设置为1（也许可以通过用户输入）。然后，只有在有意义的情况下（已输入的编号小于或等于当前库存量），才会从库存中减去该金额。

Ruby - 比较两个独立哈希中的特定值（初学者）

1 个答案: