因此，基本上我的代码在打印我希望它打印的语句之后打印出None如何停止打印此无

问题描述

因此，基本上我的代码在打印我要打印的语句后不打印任何内容。如何阻止此无打印

class Panda:
    def __init__(self,name,gender,age):
        self.name=name
        self.gender=gender
        self.age=age
    def sleep(self,time=None):
        self.time=time
        if self.time!=None:
            if self.time>=3 and self.time<=5:
                self.food='Mixed Veggies'
            if self.time>=6 and self.time<=8:
                self.food='eggplant & Tofu'
            if self.time>=9 and self.time<=11:
                self.food='broccoli Chicken'
            print('{} sleeps {} hours daily and should have {}'.format(self.name,self.time,self.food))
        else:
            print("{}'s duration is unkNown thus should have only bamboo leaves".format(self.name))

panda1=Panda("Kunfu","Male",5)
panda2=Panda("Pan Pan","Female",3)
panda3=Panda("Ming Ming",8)
print(panda2.sleep(10))
print(panda1.sleep(4))
print(panda3.sleep())

解决方法

print函数不会在Python中返回，它只会写入stdout；因此，当您为实例调用sleep方法时，它仅显示None。

要解决此问题，您需要做的是return而不是在sleep中打印，或者只是调用它而不将其包含在print语句中。

结果将是这样的，例如：

class Panda:
    def __init__(self,name,gender,age):
        self.name=name
        self.gender=gender
        self.age=age
    def sleep(self,time=None):
        self.time=time
        if self.time!=None:
            if self.time>=3 and self.time<=5:
                self.food='Mixed Veggies'
            if self.time>=6 and self.time<=8:
                self.food='Eggplant & Tofu'
            if self.time>=9 and self.time<=11:
                self.food='Broccoli Chicken'
            return '{} sleeps {} hours daily and should have {}'.format(self.name,self.time,self.food)
        else:
            return "{}'s duration is unknown thus should have only bamboo leaves".format(self.name)

panda1=Panda("Kunfu","Male",5)
panda2=Panda("Pan Pan","Female",3)
panda3=Panda("Ming Ming",8)
print(panda2.sleep(10))
print(panda1.sleep(4))
print(panda3.sleep())

或

class Panda:
    def __init__(self,time=None):
        self.time=time
        if self.time!=None:
            if self.time>=3 and self.time<=5:
                self.food='Mixed Veggies'
            if self.time>=6 and self.time<=8:
                self.food='Eggplant & Tofu'
            if self.time>=9 and self.time<=11:
                self.food='Broccoli Chicken'
            print('{} sleeps {} hours daily and should have {}'.format(self.name,self.food))
        else:
            print("{}'s duration is unknown thus should have only bamboo leaves".format(self.name))

panda1=Panda("Kunfu",8)
panda2.sleep(10)
panda1.sleep(4)
panda3.sleep()

因此，第一个打印语句归因于print方法中的sleep函数。像None一样打印print(panda1.sleep())。 sleep方法不会返回任何内容，因此不会返回None。

要摆脱None，只需使用panda1.sleep()而不是print(panda1.sleep())。

但是，更好的选择可能是返回要打印sleep函数的消息，然后使用print(panda1.sleep())

methods overloading python