根据用户输入提供的一个值从列表中删除一个字典 - python答案

【问题标题】：Delete a dict from a list based on one value provided by user input - python根据用户输入提供的一个值从列表中删除一个字典 - python
【发布时间】：2020-08-01 11:46:15
【问题描述】：

我有初始代码：

books = []


def add_book():
    name = input('Input the name of the book: ')
    author = input('Input the author: ')
    print('Book added successfully.')

    books.append(
        {
            'name': name,
            'author': author,
            'read': False
        }
    )

我需要用户能够提供书名，如果他的输入与books 中的名称匹配，则删除它所引用的整个字典。我想出了这段代码：

def delete_book():
    user_input = input('Input the name of the book to be deleted: ')

    for book in books:
        for key, value in book.items():
            if book['name'] == user_input:
                books.remove(book)

但它不起作用..我已经浏览了大约 2 小时以找到解决方案，作为初学者我无法弄清楚这一点，也许你们可以清除我的想法。

现在再看看字典中的键值read。我希望用户能够将值更改为 True。所以我尝试了很多版本，但这更难。这就是我所拥有的：

def mark_read():  # TODO REVIEW !!!!
    book_name = input('Input name of the book: ')

    for book in books:
        if book == book_name:
            user_input = input('Mark book as read? (y/N): ')
            if user_input == 'N' or 'n':
                print('No changes were made')
            elif user_input == 'Y' or 'y':
                book.update(read=True)
        else:
            print('The specified book is not currently in our database.')

那么你能告诉我我错在哪里，给我一个更好但更容易阅读的选项吗？

【问题讨论】：

Please don't add "solved" to your title or question。相反，mark an answer correct by clicking on the checkmark（你已经这样做了）。如果你收到的都没有解决你的问题，你也可以add your own answer接受。

标签： python list dictionary nested user-input

【解决方案1】：

删除代码：

def delete_book():
    user_input = input('Input the name of the book to be deleted: ')

    for i,book in enumerate(books):
        if book['name'] == user_input:
            del books[i]

标记为已读的代码：

def mark_read():  # TODO REVIEW !!!!
    book_name = input('Input name of the book: ')
    f=0 #flag to see if book is present in dict
    for book in books:
        if book['name'] == book_name:
            f=1
            user_input = input('Mark book as read? (y/N): ')
            if user_input == 'N' or 'n':
                print('No changes were made')
            elif user_input == 'Y' or 'y':
                book['read']=True
            break #if book is found, you can exit the loop early
    if f==0:
        print('The specified book is not currently in our database.')

【讨论】：

【解决方案2】：

您的代码的问题在于，当您只需要一个字段 (name) 时，您正在循环字典。因此，您正在删除带有字典第一个字段的书，但您试图再次删除带有字典下一个字段的条目，这是不可能的。

您无需遍历字典的所有字段即可仅比较一个字段。以下作品：

books =[{'name': "Hello", "author": "Arthur"}, {'name': "Hi", "author": "Vicky"}]

user_input = input('Input the name of the book to be deleted: ')

for book in books:
    if book['name'] == user_input:
        books.remove(book)
            
print(books)

输入“Hi”时的结果：

[{'name': 'Hello', 'author': 'Arthur'}]

【讨论】：