Question

这是我创建的课程

import pickle

class CarRecord:
    def __init__(self):
        self.VehicleID = ""
        self.Registration = ""
        self.DateOfRegistration = None
        self.EngineSize = 0
        self.PurchasePrice = 0.00

ThisCar = CarRecord()
Car = [ThisCar for i in range(5)]
Car[0].EngineSize = 2400
Car[1].EngineSize = 2300
Car[2].EngineSize = 2200
Car[3].EngineSize = 2100
Car[4].EngineSize = 2000

我想将这些记录写入二进制文件

CarFile = open('Cars.DAT', 'wb')
for i in range(5):
   pickle.dump(Car[i], CarFile)
print(Car)

CarFile.close()
CarFile = open('Cars.DAT', 'rb')
Car = []

print("££££££££")

并将记录追加到列表的末尾

while True:

在这里我检查文件的结尾

Car.append(pickle.load(CarFile))
CarFile.close()
print(Car)

Answer 1

试试这段代码，代码的问题是你做了一段时间的True，导致EOF，你需要指定unpickling长度，或者为编辑中指定的EOFError处理。

import pickle

class CarRecord:
    def __init__(self):
        self.VehicleID = ""
        self.Registration = ""
        self.DateOfRegistration = None
        self.EngineSize = 0
        self.PurchasePrice = 0.00

ThisCar = CarRecord()
Car = [ThisCar for i in range(5)]
Car[0].EngineSize = 2400
Car[1].EngineSize = 2300
Car[2].EngineSize = 2200
Car[3].EngineSize = 2100
Car[4].EngineSize = 2000

CarFile = open('Cars.DAT', 'wb')
for i in range(0,5):
    pickle.dump(Car[i], CarFile)
print(Car)

CarFile.close()
CarFile = open('Cars.DAT', 'rb')
Car = []

print("here")

for i in range(0,5):
    Car.append(pickle.load(CarFile))

CarFile.close()
print(Car)

编辑： - 我找到了一个更好的答案，它不使用硬编码值。 Reading from a file using pickle and for loop in python

我也会在这里发布答案。基本上它会捕获EOFError和UnpicklingError，这样当文件结束时，它就会关闭，你可以按照你想要的那样正常使用它

Car = []
CarFile = open('Cars.DAT', 'rb')
while 1:
    try:
        Car.append(pickle.load(CarFile))
    except (EOFError, UnpicklingError):
        break
CarFile.close()

这将读取EOFError：输出输出

1 个答案: