python中的内置函数getattr()介绍及示例

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getattr(object, name[, default])

Return the value of the named attribute of object. name must be a string. If the string is the name of one of the object‘s attributes, the result is the value of that attribute. For example, getattr(x, ‘foobar‘) is equivalent to x.foobar. If the named attribute does not exist, default is returned if provided, otherwise AttributeError is raised.

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‘# -*- coding: utf-8 -*-‘

__author__ = ‘lucas‘

class attrtest(object):

  def __init__(self):

    pass

  def trygetattr0(self):

    self.name = ‘lucas‘

    print self.name

    #equals to self.name

    print getattr(self,‘name‘)

  def attribute1(self,para1):

    print ‘attribute1 called and ‘+ para1+‘ is passed in as a parameter‘

  def trygetattr(self):

    fun = getattr(self,‘attribute1‘)

    print type(fun)

    fun(‘crown‘)

if __name__==‘__main__‘:

  test = attrtest()

  print ‘getattr(self,\‘name\‘) equals to self.name ‘

  test.trygetattr0()

  print ‘attribute1 is indirectly called by fun()‘

  test.trygetattr()

  print ‘attrribute1 is directly called‘

  test.attribute1(‘tomato‘)

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getattr(self,‘name‘) equals to self.name

lucas

lucas

attribute1 is indirectly called by fun()

<type ‘instancemethod‘>

attribute1 called and crown is passed in as a parameter

attrribute1 is directly called

attribute1 called and tomato is passed in as a parameter

Process finished with exit code 0

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#如果类A中有如下方法：

def addnewattributesfromotherclass(self,class_name):

    func_names = dir(class_name)

    for func_name in func_names:

      if not func_name.startswith(‘_‘):

        new_func = getattr(class_name,func_name)

        self.__setattr__(func_name,new_func())

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a = A()

b = B()

a.addnewattributesfromotherclass(b)