如何在 class 实例中使用日期时间对象？

Question

在 for 循环中创建了 Rabbit class 的一个实例，并将日期时间对象作为初始变量但所有实例都获得相同的日期时间值。我预计每个实例都有时间差；我在理解这里缺少什么？

from datetime import datetime
class Rabbit_birth:
    num_eyes = 2  # <- Class variable
    num_legs = 4
    num_ears = 2
    num_tails = 1
    num_of_rabbits = 0

    def __init__(self, name = 'Rabbit',
                 fur_colour = 'unknown',
                 eye_colour = 'unknown',
                 sex = 'unsexed',
                 breed = 'unknown',
                 dob = datetime.now(),
                 tob = datetime.now()
                 ):

        self.name = name  # <- Instance variable
        self.fur_colour = fur_colour
        self.eye_colour = eye_colour
        self.sex = sex
        self.breed = breed
        self.dob = str(dob.strftime("%x"))
        self.tob = str(tob.strftime("%X"))
        Rabbit_birth.num_of_rabbits += 1


    def display_rabbit(self):
        dob_time = self.dob+" at "+self.tob
        return ("{0.name} is a {0.sex} rabbit"
    " and has {0.fur_colour} fur and "
    "{0.eye_colour} eyes, {0.name} is "
    "of the {0.breed} breed of rabbits.\n"
    "{0.name}'s DOB is ").format(self) + dob_time         
################################################
print()

print('Number of rabbits is ',Rabbit_birth.num_of_rabbits)





rabbits=[]
def create_rabbit():
    lr=[]
    rabbit = ('name', 'fur colour', 'eye colour', 'sex', 'breed')
    for item in rabbit:
        r = input(item+' >')
        lr.append(r)
    r0,r1,r2,r3,r4=lr
    name = Rabbit_birth(r0,r1,r2,r3,r4)    
    return name
for i in range(3):

    name=create_rabbit()
    rabbits.append(name)
    print(rabbits[i].display_rabbit())

Answer 1

我明白我犯的错误了，这是在错误的范围内传递日期时间对象的问题。

这里是相关更正后的代码：

## <- class experiment
from datetime import datetime
class Rabbit_birth:
    num_eyes = 2  # <- Class variable
    num_legs = 4
    num_ears = 2
    num_tails = 1
    num_of_rabbits = 0

    def __init__(self, name = 'Rabbit',
                 fur_colour = 'unknown',
                 eye_colour = 'unknown',
                 sex = 'unsexed',
                 breed = 'unknown',
                 dob = None, # This line changed
                 tob = None  # This line changed
                 ):
        self.name = name  # <- Instance variable
        self.fur_colour = fur_colour
        self.eye_colour = eye_colour
        self.sex = sex
        self.breed = breed
        self.dob = datetime.now() # This line changed
        self.tob = datetime.now() # This line changed
        Rabbit_birth.num_of_rabbits += 1


    def display_rabbit(self):
        # This line below changed
        dob_time = str(self.dob.strftime("%x"))+" at "+str(self.tob.strftime("%X"))
        return ("{0.name} is a {0.sex} rabbit"
    " and has {0.fur_colour} fur and "
    "{0.eye_colour} eyes, {0.name} is "
    "of the {0.breed} breed of rabbits.\n"
    "{0.name}'s DOB is ").format(self) + dob_time         
################################################

如何在 class 实例中使用日期时间对象？

how to use datetime objects in a class instance?

python-3.x

class

datetime

instance-variables