class Person(object):
  def __init__(self,name):
    self.name = name
  def talk(self):
    print("%s正在交談"%self.name)

p = Person("laowang")    
print(hasattr(p,"talk"))  # True。因為存在talk方法
print(hasattr(p,"name"))  # True。因為存在name變量
print(hasattr(p,"abc"))   # False。因為不存在abc方法或變量

class Person(object):
  def __init__(self,name):
    self.name = name
  def talk(self):
    print("%s正在交談"%self.name)
p = Person("laowang")

n = getattr(p,"name")  # 獲取name變量的內(nèi)存地址
print(n)        # 此時打印的是:laowang

f = getattr(p,"talk")  # 獲取talk方法的內(nèi)存地址
f()           # 調(diào)用talk方法

我們發(fā)現(xiàn)getattr有三個參數(shù)，那么第三個參數(shù)是做什么用的呢?
s = getattr(p,"abc","not find")
print(s)        # 打印結(jié)果：not find。因為abc在對象p中找不到，本應(yīng)該報錯，但因為修改了找不到就輸出not find

def abc(self):
  print("%s正在交談"%self.name)

class Person(object):
  def __init__(self,name):
    self.name = name

p = Person("laowang")
setattr(p,"talk",abc)  # 將abc函數(shù)添加到對象中p中，并命名為talk
p.talk(p)        # 調(diào)用talk方法，因為這是額外添加的方法，需手動傳入對象


setattr(p,"age",30)   # 添加一個變量age,復(fù)制為30
print(p.age)      # 打印結(jié)果:30

class Person(object):
  def __init__(self,name):
    self.name = name
  def talk(self):
    print("%s正在交談"%self.name)

p = Person("laowang")

delattr(p,"name")    # 刪除name變量
print(p.name)      # 此時將報錯