Question

该计划的目标是：

提示用户提供所需物品数量
阅读所需的项目
提示用户购买的商品数量
阅读已购买的商品
最后，比较两个列表，看看哪些商品已被购买，哪些商品已被购买。

即

“以下是您仍需购买的物品：面包蛋蛋火腿

以下是您购买的不必要物品：芯片火鸡“

到目前为止，这是我的代码：

count = 1
count2 = 1

# of items on list
item_numN = int(raw_input("Please enter the number of items on your grocery list.\n"))

for i in range (0,item_numN):
    item_list = str(raw_input("What is the item #" + str(count) + " on your list?\n"))
    count = count + 1

# of items bought
item_numB = int(raw_input("Please enter the number of items you bought.\n"))

for i in range (0,item_numB):
    item_bought = str(raw_input("What is the item #" + str(count2) + " that you bought?\n"))
    count2 = count2 + 1

我无法弄清楚如何阅读两组独立的输入并进行比较。任何帮助将不胜感激。

Answer 1

您可以使用集来查找差异。

尽量保留原始代码：

item_numN = int(raw_input("Please enter the number of items on your grocery list.\n"))
item_list = [str(raw_input("What is the item #" + str(count + 1) + " on your list?\n")) for count in range(item_numN)]

item_numB = int(raw_input("Please enter the number of items you bought.\n"))
item_bought = [str(raw_input("What is the item #" + str(count + 1) + " that you bought?\n")) for count in range(item_numB)]

items_needed = set(item_list) - set(item_bought)
print 'You still need {}.'.format(', '.join(items_needed))

这是一个示例会话：

Please enter the number of items on your grocery list.
3
What is the item #1 on your list?
apples
What is the item #2 on your list?
pears
What is the item #3 on your list?
beer
Please enter the number of items you bought.
4
What is the item #1 that you bought?
beer
What is the item #2 that you bought?
paper
What is the item #3 that you bought?
pencil
What is the item #4 that you bought?
roses
You still need apples, pears.

相比之下，未在列表中购买的商品将是set(item_bought) - set(item_list)。

Answer 2

这是作业吗？

你缺少的第一件事是你需要创建空列表然后追加给他们

像

这样的东西

item_bought=[]    
for i in range (0,item_numB):
        item_bought.append(str(raw_input("What is the item #" + str(count2) + " that you bought?\n")))

然后你就可以比较它们的分类和循环。

Answer 3

Python中的列表和集合没有预设的大小限制，它们可以说无穷无尽。所以你真的不需要问用户购买了多少件物品。你可以提示这样的事情：

items_bought=[]
items_to_buy=[]
item_count=1
while item != 'Done' or item != 'done':
    item = str(raw_input("Add item #%i or type done if you are finished"%item_count))
    items_bought.append(item)
    item_count+=1
item_count-=1 #due to last iteration, when user decides, that this is it, item count will be by 1 higher

购买清单也可以。注释集每个项目只包含1个实例，列表可以包含许多可重复的项目。参考有关Python数据sructs的文档：Python Data Structures

更新：要了解可迭代数据结构，这里有一些提示：您可以像这样调用列表项： LIST_NAME [ITEM_NUMBER] 枚举从0开始，因此列表中的项目将是：list_name [0]，list_name 1 ... list_name [n-1]，共有n个项目。切片。您可以在python中对iterables进行切片，如下所示： LIST_NAME [START_POSITION：end_position：步骤]。您也可以从列表末尾切换到开头。这是关于切片的堆栈溢出线程的链接：Slicing in Python

祝你好运，Python是一门很好的学习语言，你一定很喜欢它。

Python：杂货清单/比较两组用户输入

3 个答案: