对我来说，getattr是最简单的解释方式:

它允许您根据字符串的内容调用方法，而不是键入方法名称。

例如，你不能这样做:

obj = MyObject()
for x in ['foo', 'bar']:
    obj.x()

因为x不是内置类型，而是str。然而，你可以这样做:

obj = MyObject()
for x in ['foo', 'bar']:
    getattr(obj, x)()

它允许您根据输入动态地连接对象。我发现它在处理自定义对象和模块时很有用。

我认为这个例子是不言自明的。它运行第一个参数的方法，其名称在第二个参数中给出。

class MyClass:
   def __init__(self):
      pass
   def MyMethod(self):
      print("Method ran")

# Create an object
object = MyClass()
# Get all the methods of a class
method_list = [func for func in dir(MyClass) if callable(getattr(MyClass, func))]
# You can use any of the methods in method_list
# "MyMethod" is the one we want to use right now

# This is the same as running "object.MyMethod()"
getattr(object,'MyMethod')()

我有时使用getattr(..)在代码中使用属性之前惰性地初始化次要属性。

比较以下内容:

class Graph(object):
    def __init__(self):
        self.n_calls_to_plot = 0

    #...
    #A lot of code here
    #...

    def plot(self):
        self.n_calls_to_plot += 1

:

class Graph(object):
    def plot(self):
        self.n_calls_to_plot = 1 + getattr(self, "n_calls_to_plot", 0)

The advantage of the second way is that n_calls_to_plot only appears around the place in the code where it is used. This is good for readability, because (1) you can immediately see what value it starts with when reading how it's used, (2) it doesn't introduce a distraction into the __init__(..) method, which ideally should be about the conceptual state of the class, rather than some utility counter that is only used by one of the function's methods for technical reasons, such as optimisation, and has nothing to do with the meaning of the object.

# getattr

class hithere():

    def french(self):
        print 'bonjour'

    def english(self):
        print 'hello'

    def german(self):
        print 'hallo'

    def czech(self):
        print 'ahoj'

    def noidea(self):
        print 'unknown language'


def dispatch(language):
    try:
        getattr(hithere(),language)()
    except:
        getattr(hithere(),'noidea')()
        # note, do better error handling than this

dispatch('french')
dispatch('english')
dispatch('german')
dispatch('czech')
dispatch('spanish')

对我来说，getattr是最简单的解释方式:

它允许您根据字符串的内容调用方法，而不是键入方法名称。

例如，你不能这样做:

obj = MyObject()
for x in ['foo', 'bar']:
    obj.x()

因为x不是内置类型，而是str。然而，你可以这样做:

obj = MyObject()
for x in ['foo', 'bar']:
    getattr(obj, x)()

它允许您根据输入动态地连接对象。我发现它在处理自定义对象和模块时很有用。

我在Python2.7.17中尝试过

有些人已经回答了。不过我已经试过打电话了 getattr(obj， 'set_value')，这没有执行set_value方法，所以我改为getattr(obj， 'set_value')()——>这有助于调用相同的。

示例代码:

示例1:

    class GETATT_VERIFY():
       name = "siva"
       def __init__(self):
           print "Ok"
       def set_value(self):
           self.value = "myself"
           print "oooh"
    obj = GETATT_VERIFY()
    print getattr(GETATT_VERIFY, 'name')
    getattr(obj, 'set_value')()
    print obj.value