“‘str”对象没有属性“passengerName”-使用内置的Python函数

Question

class Flight():  # Flight Class (MAIN)
    def __init__(self, airlineName, departureAirport, arrivalAirport):  # Constructor Method
        self.airlineName: str  # Declaring attributes & Setting Types
        self.departureAirport: str  # Declaring attributes & Setting Types
        self.arrivalAirport: str  # Declaring attributes & Setting Types

    def setAirlineName(self, airlineName):  # Mutator Method
        self.airlineName = airlineName

    def getAirlineName(self):  # Accessor Method
        if len(self.airlineName) > 0:  # Error Checking
            return self.airlineName
        else:
            return "No airline name set"

    def setDepartureAirport(self, departureAirport):  # Mutator Method
        self.departureAirport = departureAirport

    def getDepartureAirport(self):  # Accessor Method
        if len(self.departureAirport) > 0:  # Error Checking
            return self.departureAirport
        else:
            return "No departure airport set"

    def setArrivalAirport(self, arrivalAirport):  # Mutator Method
        self.arrivalAirport = arrivalAirport

    def getArrivalAirport(self):  # Accessor Method
        if len(self.arrivalAirport) > 0:  # Error Checking
            return self.arrivalAirport
        else:
            return "No arrival airport set"

    def __eq__(self, otherFlight):
        return (self.airlineName == otherFlight.airlineName)

    def __str__(self):  # Overiding Method
        return "\n==================================================\n++++++++++++++++++ Flight Info ++++++++++++++++++\n==================================================\nAirline Name: " + self.airlineName + "\Departure Airport: " + self.departureAirport + "\nArrival Airport: " + self.arrivalAirport


class PassengerFlight(Flight):  # PassengerFlight Class (EXTENDS MAIN)
    def __init__(self, airlineName, departureAirport, arrivalAirport, passengerList, flightType, baggageWeight):  # Constructor Method
        super().__init__(airlineName, departureAirport, arrivalAirport)
        self.passengerList: list  # Declaring attributes & Setting Types
        self.flightType: str  # Declaring attributes & Setting Types
        self.baggageWeight: float  # Declaring attributes & Setting Types

    def setPassengerName(self, passengerList):  # Mutator Method
        self.passengerList = passengerList

    def getPassengerName(self):  # Accessor Method
        if len(self.passengerList) > 0:  # Error Checking
            return self.passengerList
        else:
            return "Passenger List Not Set"

    def setFlightType(self, flightType):  # Mutator Method
        self.flightType = flightType

    def getFlightType(self):  # Accessor Method
        if len(self.flightType) > 0:  # Error Checking
            return self.flightType
        else:
            return "No Flight Type Set"

    def setBaggageWeight(self):  # Mutator Method
        baggageWeight = 0
        for i in range(len(self.passengerList)):  # Iterates through passenger list
            baggageWeight += 50.00  # For each passenger in the list add 50KG to baggage variable
        self.baggageWeight = baggageWeight  # Set our attribute equal to the variable

    def getBaggageWeight(self):  # Accessor Method
        if self.baggageWeight == 0:
            return "No Baggage Weight Set"
        else:
            return self.baggageWeight

    def __str__(self):  # Overiding Method
        return super().__str__() + "\nPassenger Names: " + str(self.getPassengerName()) + "\nFlight Type: " + self.flightType + "\nBaggage Weight: " + str(self.baggageWeight) + '(KG) \n==================================================\n'


class CargoFlight(Flight):  # CargoFlight Class (EXTENDS MAIN)
    def __init__(self, airlineName, departureAirport, arrivalAirport, cargoType, cargoWeight, liveAnimals):  # Constructor Method
        super().__init__(airlineName, departureAirport, arrivalAirport)
        self.cargoType: str  # Declaring attributes & Setting Types
        self.cargoWeight: float  # Declaring attributes & Setting Types
        self.amountPallets: int  # Declaring attributes & Setting Types
        self.liveAnimals: bool  # Declaring attributes & Setting Types

    def setCargoType(self, cargoType):  # Mutator Method
        self.cargoType = cargoType

    def getCargoType(self):  # Accessor Method
        if len(self.cargoType) > 0:  # Error Checking
            return self.cargoType
        else:
            return "No Cargo Type Set"

    def setAmountPallets(self, amountPallets):  # Mutator Method
        self.amountPallets = amountPallets

    def getAmountPallets(self):  # Accessor Method
        if self.amountPallets != 0:  # Error Checking
            return self.amountPallets
        else:
            return "Amount of pallets not set"

    def setCargoWeight(self):  # Mutator Method
        avgCargoWeight = 114  # Googled average weight for airline pallet
        # Multiply the average cargo weight by the amount of pallets and set it to our attribute
        self.cargoWeight = avgCargoWeight * self.amountPallets

    def getCargoWeight(self):  # Accessor Method
        if self.cargoWeight == 0:  # Error Checking
            return "No Cargo Weight Set"
        else:
            return self.cargoWeight

    def setLiveAnimals(self, liveAnimals):  # Mutator Method
        if liveAnimals == True:  # If it's set to true
            self.liveAnimals = True  # set the
        else:
            self.liveAnimals = False

    def getLiveAnimals(self):
        if self.liveAnimals == True:  # Error Checking
            return "There are live animals on-board"
        else:
            return "There are no live animals on-board"

    def __str__(self):  # Overiding Method
        return super().__str__() + "\nCargo Type: " + self.getCargoType() + "\nCargo Pallets: " + str(self.getAmountPallets()) + "\nCargo Weight: " + str(self.getCargoWeight()) + "\nIs there live animals?: " + str(self.getLiveAnimals()) + "\n==================================================\n"


# Passengers Class (Implementation of 1:0..M aggregation relationship)
class Passengers:
    def __init__(self, passengerName, passengerWeight):  # Constructor Method
        # Implementing the 1:0..M aggregation relationship between Passengers and PassengerFlight
        self.passengerName: list  # Declaring attributes & Setting Types
        self.passengerWeight: int  # Declaring attributes & Setting Types

    def setPassengerName(self, passengerName):  # Mutator Method
        self.passengerName = passengerName

    def getPassengerName(self):  # Accessor Method
        if len(self.passengerName) > 0:
            return self.passengerName
        else:
            return "Passenger Name List Not Set"

    def setPassengerWeight(self):
        passengerWeight = 0
        # For i in lenth of self.passengerName variable
        for i in range(len(self.passengerName)):
            # Add 80KG (Avg Weight) to the passengerWeight variable
            passengerWeight += 80.00
        # Set our attribute equal to the variable
        self.passengerWeight = passengerWeight

    def getPassengerWeight(self):  # Acessor Method
        if self.passengerWeight != 0:
            return self.passengerWeight
        else:
            return "No passenger Weight Set"

    def getPassengerCount(self):  # Accessor Method
        return len(self.passengerName)

    def __str__(self):  # Overiding Method
        return "==================================================\n+++++++++++++++ Passenger Info +++++++++++++++\n==================================================\nPassenger Count: " + str(self.getPassengerCount()) + "\nPassenger Weight: " + str(self.getPassengerWeight()) + "(KG)\n==================================================\n"


class AirplaneType:  # AirplaneType Class (Aggregation (1:1) Relationship)
    def __init__(self, airplaneType, cargoWeight, Flight):  # Constructor Method
        self.cargoWeight: int  # Declaring attributes & Setting Types
        self.totalWeight: int  # Declaring attributes & Setting Types
        self.Flight = Flight  # Declaring attributes & Setting Types

    def setCargoWeight(self, cargoWeight):  # Mutator method
        self.cargoWeight = cargoWeight

    def getCargoWeight(self):  # Accessor Method
        if self.cargoWeight != 0:
            return self.cargoWeight
        else:
            return "No cargo weight set"

    def setTotalWeight(self, passengerWeight, passengerBaggage):  # Mutator method
        totalWeight = 0  # Initializing variable to 0
        if passengerWeight != 0 or self.cargoWeight != 0:  # Checks values are not 0
            # Sets totalWeight vaiable = to passengerWeight, passengerBaggage & cargoWeight
            totalWeight += passengerWeight + passengerBaggage + self.cargoWeight
        else:
            print("Values not set correctly, please try again!")  # Error checking
        self.totalWeight = totalWeight

    def getTotalWeight(self):  # Accessor Method
        if self.totalWeight != 0:
            return self.totalWeight
        else:
            return "Total weight not set"

    # If, elif, else statement that gets the total weight and declares what plane they should use based on info given
    def getAirplaneType(self):  # Accessor Method
        if self.totalWeight >= 0 and self.totalWeight < 500:
            return "Airbus A320/Boeing 737"
        elif self.totalWeight >= 500 and self.totalWeight < 1000:
            return "Airbus A321/Boeing 757"
        elif self.totalWeight >= 1000 and self.totalWeight < 1500:
            return "Airbus A330/Boeing 787"
        elif self.totalWeight >= 1500 and self.totalWeight < 2000:
            return "Airbus A350/Boeing 777"
        elif self.totalWeight >= 2000:
            return "Airbus A380/Boeing 747"
        else:
            print('Error: No suitable aircraft found')

    def __str__(self):  # Overiding Method
        return "==================================================\n++++++ Aircraft Information (Pilot & Staff) ++++++\n==================================================\nAirplane Type Recommended: " + self.getAirplaneType() + "\nAirplane Weight: " + str(self.totalWeight) + "(KG)\n==================================================\n"


##########################################################
#           Calling PassengerFlight Class           #
##########################################################
# Initialize Class & Set to Variable
passenger = PassengerFlight(None, None, None, None, None, None)
passenger.setAirlineName('Aer Lingus')  # Set mutators & values
passenger.setArrivalAirport('Chicago O\'Hare Intl')  # Set mutators & values
passenger.setDepartureAirport('Dublin')  # Set mutators & values
passenger.setFlightType('Long Haul')  # Set mutators & values
passenger.setPassengerName(['Passenger 1', 'Passenger 2',
                            'Passenger 3', 'Passenger 4', 'Passenger 5', 'Passenger 6'])  # Set mutators & values
passenger.setBaggageWeight()  # Set mutators & values
print(passenger)  # uses the overridden _str_ method to print detail of the class
##########################################################
#           Calling Passengers Class           #
##########################################################
# Initialize Class & Set Attributes to None
passengerInfo = Passengers(None, None)
passengerInfo.setPassengerName(
    passenger.passengerList)  # Set mutators & values
passengerInfo.setPassengerWeight()
print(passengerInfo)  # uses the overridden _str_ method to print detail of the
##########################################################
#           Calling AirplaneType Class           #
##########################################################
# Initialize Class & Set Attributes to None
passengerFlight = AirplaneType(None, None, Flight)
passengerFlight.setCargoWeight(0)  # Set mutators & values
passengerFlight.setTotalWeight(
    passengerInfo.passengerWeight, passenger.baggageWeight)  # Set mutators & values
# uses the overridden _str_ method to print detail of the class
print(passengerFlight)
##########################################################
##########################################################
#           Calling CargoFlight Class           #
##########################################################
# Initialize Class & Set Attributes to None
cargo = CargoFlight(None, None, None, None, None, None)
cargo.setAirlineName('DHL')  # Set mutators & values
cargo.setArrivalAirport('JFK Intl')  # Set mutators & values
cargo.setDepartureAirport('Dublin Intl')  # Set mutators & values
cargo.setCargoType('General')  # Set mutators & values
cargo.setLiveAnimals(True)  # Set mutators & values
cargo.setAmountPallets(10)  # Set mutators & values
cargo.setCargoWeight()  # Set mutators & values
print(cargo)  # uses the overridden _str_ method to print detail of the class
##########################################################
#           Calling AirplaneType Class           #
##########################################################
# Initialize Class & Set Attributes to None
cargoFl = AirplaneType(None, None, Flight)
cargoFl.setCargoWeight(cargo.cargoWeight)  # Set mutators & values
cargoFl.setTotalWeight(0, 0)  # Set mutators & values
print(cargoFl)  # uses the overridden _str_ method to print detail of the class
##########################################################
print(cargo == passenger)
##########################################################
# In-Built Functions

def getPassengers(p):
    return p.passengerName


print(min(passengerInfo.passengerName, key=getPassengers))

你好啊，

我在大学的python代码中遇到了一个错误。我必须添加使用python内置函数的排序功能。讲座希望我们使用辅助函数，就像上面最后几行一样。当我尝试运行这个函数时，我在def getPassengers(p)函数上得到一个错误：

Exception has occurred: AttributeError 'str' object has no attribute 'passengerName'

我可以看到它选择了变量'Passenger 1‘，并显示为一个本地变量，这是正确的，因为运行min()将选择第一个passenger，因为它们都是相同的长度。

有人有什么建议来解决这个问题吗？

谢谢!

Answer 1

passengerInfo.passengerName包含以下['Passenger 1', 'Passenger 2', 'Passenger 3', 'Passenger 4', 'Passenger 5', 'Passenger 6']，它是一个字符串列表。在这种情况下，作为键传递给函数min的是该列表的元素，而不是passengerInfo对象。在这种情况下，可以在没有任何个性化键的情况下对列表元素应用min函数。min函数将应用于列表的字符串值。

下面返回正确的min

>>> print(min(passengerInfo.passengerName))
'Passenger 1'

现在，要通过检查字符串的长度来获得最小值，可以执行以下操作

>>> print(min(passengerInfo.passengerName, key=lambda x: len(x)))

Answer 2

您的实现的问题是，您将一个参数传递给str类型的getPassengers，然后尝试访问该str上的passengerName属性，这将不起作用。如果您希望按姓名长度对这些乘客进行排序，则甚至不需要为此定义自定义函数。您可以只将len作为key参数传递：

>>> len_sorted = sorted(passengerInfo.passengerName, key=len)
['Passenger 1', 'Passenger 2', 'Passenger 3', 'Passenger 4', 'Passenger 5', 'Passenger 6']

然后，您只需编写以下代码即可访问这些文件上的min、max等：

>>> min(len_sorted)
'Passenger 1'

>>> max(len_sorted)
'Passenger 6'

Answer 3

传递给min的'key‘参数是要在passengerInfo.passengerName上执行的函数。

因此，您在passengerName (类型为str)上调用'getPassengers‘函数，这会导致错误