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詳解Python3 中hasattr()、getattr()、setattr()、delattr()函數(shù)及示例代碼數(shù)

更新時(shí)間：2018年04月18日 09:31:59 作者：1024python

本文通過(guò)示例代碼給大家詳細(xì)介紹了Python3 中hasattr()、getattr()、setattr()、delattr()函數(shù)，非常不錯(cuò)，具有參考借鑒價(jià)值，需要的朋友參考下吧

hasattr()函數(shù)

hasattr()函數(shù)用于判斷是否包含對(duì)應(yīng)的屬性

語(yǔ)法：

hasattr(object,name)

參數(shù)：

object--對(duì)象

name--字符串，屬性名

返回值：

如果對(duì)象有該屬性返回True，否則返回False

示例：

class People:
  country='China'
  def __init__(self,name):
    self.name=name
  def people_info(self):
    print('%s is xxx' %(self.name))
obj=People('aaa')
print(hasattr(People,'country'))
#返回值：True
print('country' in People.__dict__)
#返回值：True
print(hasattr(obj,'people_info'))
#返回值：True
print(People.__dict__)
##{'__module__': '__main__', 'country': 'China', '__init__': <function People.__init__ at 0x1006d5620>, 'people_info': <function People.people_info at 0x10205d1e0>, '__dict__': <attribute '__dict__' of 'People' objects>, '__weakref__': <attribute '__weakref__' of 'People' objects>, '__doc__': None}

getattr()函數(shù)

描述：

getattr()函數(shù)用于返回一個(gè)對(duì)象屬性值

語(yǔ)法：

getattr(object,name,default)

參數(shù)：

object--對(duì)象

name--字符串，對(duì)象屬性

default--默認(rèn)返回值，如果不提供該參數(shù)，在沒(méi)有對(duì)于屬性時(shí)，將觸發(fā)AttributeError。

返回值：

返回對(duì)象屬性值

class People:
  country='China'
  def __init__(self,name):
    self.name=name

  def people_info(self):
    print('%s is xxx' %(self.name))
obj=getattr(People,'country')
print(obj)
#返回值China
#obj=getattr(People,'countryaaaaaa')
#print(obj)
#報(bào)錯(cuò)
# File "/getattr()函數(shù).py", line 32, in <module>
#   obj=getattr(People,'countryaaaaaa')
# AttributeError: type object 'People' has no attribute 'countryaaaaaa'
obj=getattr(People,'countryaaaaaa',None)
print(obj)
#返回值None

setattr()函數(shù)

描述：

setattr函數(shù)，用于設(shè)置屬性值，該屬性必須存在

語(yǔ)法：

setattr(object,name,value)

參數(shù)：

object--對(duì)象

name--字符串，對(duì)象屬性

value--屬性值

返回值：

無(wú)

class People:
  country='China'
  def __init__(self,name):
    self.name=name
  def people_info(self):
    print('%s is xxx' %(self.name))
obj=People('aaa')
setattr(People,'x',111) #等同于People.x=111
print(People.x)
#obj.age=18
setattr(obj,'age',18)
print(obj.__dict__)
#{'name': 'aaa', 'age': 18}
print(People.__dict__)
#{'__module__': '__main__', 'country': 'China', '__init__': <function People.__init__ at 0x1007d5620>, 'people_info': <function People.people_info at 0x10215d1e0>, '__dict__': <attribute '__dict__' of 'People' objects>, '__weakref__': <attribute '__weakref__' of 'People' objects>, '__doc__': None, 'x': 111}

delattr()函數(shù)

描述：

delattr函數(shù)用于刪除屬性

delattr(x,'foobar)相當(dāng)于del x.foobar

語(yǔ)法：

setattr(object,name)

參數(shù)：

object--對(duì)象

name--必須是對(duì)象的屬性

返回值：

無(wú)

示例：

class People:
  country='China'
  def __init__(self,name):
    self.name=name
  def people_info(self):
    print('%s is xxx' %(self.name))
delattr(People,'country') #等同于del People.country
print(People.__dict__)
{'__module__': '__main__', '__init__': <function People.__init__ at 0x1006d5620>, 'people_info': <function People.people_info at 0x10073d1e0>, '__dict__': <attribute '__dict__' of 'People' objects>, '__weakref__': <attribute '__weakref__' of 'People' objects>, '__doc__': None}

補(bǔ)充示例：

class Foo:
  def run(self):
    while True:
      cmd=input('cmd>>: ').strip()
      if hasattr(self,cmd):
        func=getattr(self,cmd)
        func()
  def download(self):
    print('download....')
  def upload(self):
    print('upload...')
# obj=Foo()
# obj.run()

總結(jié)

以上所述是小編給大家介紹的詳解Python3 中hasattr()、getattr()、setattr()、delattr()函數(shù)，希望對(duì)大家有所幫助，如果大家有任何疑問(wèn)請(qǐng)給我留言，小編會(huì)及時(shí)回復(fù)大家的。在此也非常感謝大家對(duì)腳本之家網(wǎng)站的支持！

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