如何在python中访问嵌套字典键的值？

我有嵌套的字典，我想更新第二个字典“key”值的值，这样它也应该反映字典值

class Screen_Seat:
   def __init__(self,screen,show,num_seats,day):
      self.screen_id = screen
      self.show = show
      self.num_seats = num_seats

     self.seats = {('screen1','day4'):{'show1':100,'show2':100,'show3':100,'show4':100},
                   ('screen1','day5'):{'show1':100,'show2':100,'show3':100,'show4':100},
                   ('screen1','day6'):{'show1':100,'show2':100,'show3':100,'show4':100},
                   ('screen1','day7'):{'show1':100,'show2':100,'show3':100,'show4':100},}

我想更新以下键的值

self.seats['screen1','day4','show4'] =90

以便：

self.seats = {('screen1','day4'):{'show1':100,'show2':100,'show3':100,'show4':**90**},
                       ('screen1','day5'):{'show1':100,'show2':100,'show3':100,'show4':100},
                       ('screen1','day6'):{'show1':100,'show2':100,'show3':100,'show4':100},
                       ('screen1','day7'):{'show1':100,'show2':100,'show3':100,'show4':100},}

如何在python中实现这一点

编辑：

输出：

2
seat booked
90
seat booked

第二次应该打印“对不起，第一屏没有座位”。请尝试其他屏幕的

---

帮助我识别代码中的问题？

您的字典有两个嵌套级别，一个使用“screenX”、“dayX”元组索引，另一个使用showX字符串索引。遵守以下规定：

>>> foo.seats['screen1', 'day4']
{'show4': 90, 'show2': 100, 'show1': 100, 'show3': 100}
>>> foo.seats['screen1', 'day4']['show4']
90

第一个表达式提供了一个字典，为了得到所需的元素，您必须再次索引该字典。所以最后的表达是：

foo.seats['screen1', 'day4']['show4']
#         ^                  ^
#         |                  |
#         +-- First level    +-- Second level

使用以下命令：

self.seats[('screen1', 'day4')]['show4'] = 90

输出：

首先访问screen1 day4，通过'screen1'，'day4'元组作为self.seats字典中的键显示。然后通过“show4”访问内部字典的“show4”键，并将其值设置为90

看起来您对python还不熟悉。让我们试着通过以下三个步骤来理解思维过程

步骤1：

“screen1”，“day4”提供对{'show1'：100，'show2'：100，'show3'：100，'show4'：100}内部字典的访问

self.seats[('screen1', 'day4')]
{'show1': 100, 'show2': 100, 'show3': 100, 'show4': 100}

步骤2：

现在，通过上一步获得的字典中的“show4”键访问show4

self.seats[('screen1', 'day4')]['show4']
100

步骤3：

将screen1-day4-show4获得的值更新为90

self.seats[('screen1', 'day4')]['show4'] = 90

self.seats[('screen1', 'day4')]['show4']
90

代码解决方案：

检查这种方法是否适合您

class ScreenBooking(object):

    def __init__(self):
        super(ScreenBooking, self).__init__()
        self.seats = {
            ('screen1','day4'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen1','day5'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen1','day6'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen1','day7'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen2','day1'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen2','day2'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen2','day3'):{'show1':100,'show2':100,'show3':100,'show4':100},
        }
        self.shows = ['show1', 'show2', 'show3', 'show4']


    def check_valid_details(self, screen, show, day):
        """
        Check if booking details are valid and return True/False accordingly.
        """
        if (screen, day) not in self.seats or show not in self.shows:
            return  False
        return True

    def book_seats(self, screen, show, no_of_seats, day):
        """
        Book seats after checking valid booking details and the remaining seats.
        """
        valid_details = self.check_valid_details(screen, show, day)
        if not valid_details:
            print 'Invalid booking details!'
            return
        show_total_seats = self.seats[(screen, day)][show]
        if show_total_seats > int(no_of_seats):
            show_remaining_seats = show_total_seats - int(no_of_seats)
            self.seats[(screen, day)][show] = show_remaining_seats #update the seats count
            print '%s seat(s) booked'%(no_of_seats)
        else:
            print 'Sorry, No seats available in %s. Please try other Screens'%(screen)

a1 = ScreenBooking()
a1.book_seats('screen1','show1','98','day4')
a1.book_seats('screen1','show1','10','day4')

---

self.seats['screen1'，'day4']['show4']=90类值中没有更新新值。上面的代码中没有screen7。此外，请按照大写字母符号命名类@RahulGupta更新了类。您之所以获得此输出，是因为您再次使用screen_seat类中定义的座位值创建screen_预订的新实例。嘿，Lucifier！我已经为你的问题编写了解决方案。看看它是否适合你。

self.seats[('screen1', 'day4')]['show4'] = 90

self.seats[('screen1', 'day4')]['show4']
90

class ScreenBooking(object):

    def __init__(self):
        super(ScreenBooking, self).__init__()
        self.seats = {
            ('screen1','day4'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen1','day5'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen1','day6'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen1','day7'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen2','day1'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen2','day2'):{'show1':100,'show2':100,'show3':100,'show4':100},
            ('screen2','day3'):{'show1':100,'show2':100,'show3':100,'show4':100},
        }
        self.shows = ['show1', 'show2', 'show3', 'show4']


    def check_valid_details(self, screen, show, day):
        """
        Check if booking details are valid and return True/False accordingly.
        """
        if (screen, day) not in self.seats or show not in self.shows:
            return  False
        return True

    def book_seats(self, screen, show, no_of_seats, day):
        """
        Book seats after checking valid booking details and the remaining seats.
        """
        valid_details = self.check_valid_details(screen, show, day)
        if not valid_details:
            print 'Invalid booking details!'
            return
        show_total_seats = self.seats[(screen, day)][show]
        if show_total_seats > int(no_of_seats):
            show_remaining_seats = show_total_seats - int(no_of_seats)
            self.seats[(screen, day)][show] = show_remaining_seats #update the seats count
            print '%s seat(s) booked'%(no_of_seats)
        else:
            print 'Sorry, No seats available in %s. Please try other Screens'%(screen)

a1 = ScreenBooking()
a1.book_seats('screen1','show1','98','day4')
a1.book_seats('screen1','show1','10','day4')