Question

如果我在字符串中有对象和方法名称，我该如何调用该方法？

class Foo:
    def bar1(self):
        print 1
    def bar2(self):
        print 2

def callMethod(o, name):
    ???

f = Foo()
callMethod(f, "bar1")

Answer 1

简单的一个：

class Foo:
    def bar1(self):
        print 1
    def bar2(self):
        print 2

def callMethod(o, name):
    getattr(o, name)()


f = Foo()
callMethod(f, "bar1")

查看getattr

您还可以使用setattr按名称设置Class属性。

Answer 2

我有类似的问题，想通过引用调用实例方法。这是我发现的有趣的事情：

instance_of_foo=Foo()

method_ref=getattr(Foo, 'bar')
method_ref(instance_of_foo) # instance_of_foo becomes self

instance_method_ref=getattr(instance_of_foo, 'bar')
instance_method_ref() # instance_of_foo already bound into reference

Python太神奇了！

Answer 3

getattr(globals()['Foo'](), 'bar1')()
getattr(globals()['Foo'](), 'bar2')()

无需首先实例化Foo！

Answer 4

def callmethod(cls, mtd_name):    
    method = getattr(cls, mtd_name)
    method()

Answer 5

这是一个使用Python装饰器的更通用的版本。你可以用短名或长名打电话。我发现在使用short和long子命令实现CLI时很有用。

Python装饰器很精彩。 Bruce Eckel（Thinking in Java）在这里精美地描述了Python装饰器。

http://www.artima.com/weblogs/viewpost.jsp?thread=240808 http://www.artima.com/weblogs/viewpost.jsp?thread=240845

enum CellValue {
    Undefined, One, Two, Three, Four, Five, Six, Seven, Eight, Nine;
    public static CellValue fromInteger(int x) {
        switch (x) {
        case 0:
            return Undefined;
        case 1:
            return One;
        case 2:
            return Two;
        case 3:
            return Three;
        case 4:
            return Four;
        case 5:
            return Five;
        case 6:
            return Six;
        case 7:
            return Seven;
        case 8:
            return Eight;
        case 9:
            return Nine;
        }
        return null;
    }

    public static int toInteger(CellValue value) throws Exception {
        switch (value) {
        case Undefined:
            throw new Exception("Undefined cell value");
        case One:
            return 1;
        case Two:
            return 2;
        case Three:
            return 3;
        case Four:
            return 4;
        case Five:
            return 5;
        case Six:
            return 6;
        case Seven:
            return 7;
        case Eight:
            return 8;
        case Nine:
            return 9;
        }
        throw new Exception("Undefined Cell Value");
    }
}

按名称调用Python方法

5 个答案: