您能解释一下吗，代码课程中的一堂课

Question

我当时在代码学院学习代码，当时我在其中编写代码，但没有得到练习的解决方案，我单击了给我解决方案选项，然后得到了我不理解该程序的解决方案。prices = {"banana": 4,"apple": 2,"orange": 1.5,"pear": 3}stock = {"banana": 6, "apple": 0, "orange": 32, "pear": 15}for food in prices:  print food  print "price: %s" % prices[food]  print "stock: %s" % stock[food]然后打印出来orangeprice: 1.5stock: 32pearprice: 3stock: 15bananaprice: 4stock: 6appleprice: 2stock: 0你能解释一下它的过程吗？它如何打印上面给出的输出

Answer 1

知道这个问题会有所帮助。但是我可以尝试在不知道问题的情况下从高层次上解释该程序。

prices = {"banana": 4,"apple": 2,"orange": 1.5,"pear": 3}

stock = {"banana": 6, "apple": 0, "orange": 32, "pear": 15}

这是两个字典的定义，第一个字典仅存储每个水果的价格，第二个字典存储存储中的水果数量（库存）。

for food in prices: ### For loop iterates over the Keys of the dict (fruitnames)

    print food ## printing current key for iteration

    print "price: %s" % prices[food] ## printing price of the fruit

    print "stock: %s" % stock[food] ## printing stock of the fruit.

顺便说一下，这看起来像Python2语法，因为该print语句没有括号。我强烈建议改为学习python3。

Answer 2

您有两个字典prices，分别是和stock

prices = {"banana": 4,"apple": 2,"orange": 1.5,"pear": 3}

stock = {"banana": 6, "apple": 0, "orange": 32, "pear": 15}

你遍历keys的prices通过字典for food in prices:此行。

阅读此代码的注释：

prices = {"banana": 4,"apple": 2,"orange": 1.5,"pear": 3} #prices dict

stock = {"banana": 6, "apple": 0, "orange": 32, "pear": 15} #stock dict

for food in prices: #iterate over the keys of prices dict

  print food #print the key

  print "price: %s" % prices[food] #print the value of prices dict at food key

  print "stock: %s" % stock[food] #print the value of stock dict at food key