Python3:使用参数字典动态调用方法
我需要能够在一个类上动态调用一个方法,该类接受基于字符串名称和变量字典的各种参数。我知道如何使用inspect模块查找签名,并且可以使用getattr获取方法,但是我不知道如何以正确的顺序分配参数,以便以纯动态的方式调用它Python3:使用参数字典动态调用方法,python,python-3.x,Python,Python 3.x,我需要能够在一个类上动态调用一个方法,该类接受基于字符串名称和变量字典的各种参数。我知道如何使用inspect模块查找签名,并且可以使用getattr获取方法,但是我不知道如何以正确的顺序分配参数,以便以纯动态的方式调用它 class MyClass(): def call_me(a, b, *args, foo='bar', **kwargs): print('Hey, I got called!') command = { 'action':'c
class MyClass():
def call_me(a, b, *args, foo='bar', **kwargs):
print('Hey, I got called!')
command = {
'action':'call_me',
'parameters':{
'a': 'Apple',
'b': 'Banana',
'args':['one','two','three','four'],
'foo':'spam',
'clowns':'bad',
'chickens':'good'
}
}
me = MyClass()
action = getattr(me,command['action'])
... now what?
我需要能够动态调用此函数,就像使用此代码一样,而不预先知道方法的实际参数:
a = command['parameters']['a']
b = command['parameters']['b']
args = command['parameters']['args']
foo = command['parameters']['foo']
kwargs = {
'clowns': command['parameters']['clowns'],
'chickens':command['parameters']['chickens']
}
value = action(a, b, *args, foo=foo, **kwargs)
当然,有一种很好的蟒蛇式方法可以做到这一点
编辑:修复了getattr直接调用MyClass而不是MyClass实例的问题。尝试如下操作:
action = getattr(me,command['action'])
action(**{'a': 'Apple',
'b': 'Banana',
'args':['one','two','three','four'],
'foo':'spam',
'clowns':'bad',
'chickens':'good'
})
这是迄今为止我发现的最好的方法,可以捕获正常args、*args、关键字args和**kwargs的所有可能组合,而不会出现任何错误:
import inspect
class MyClass():
def a(self):
pass
def b(self,foo):
pass
def c(self,foo,*extras):
pass
def d(self,foo,food='spam'):
pass
def e(self,foo,**kwargs):
pass
def f(self,foo,*extras,food='spam'):
pass
def g(self,foo,*extras,**kwargs):
pass
def h(self,foo,*extras,food='spam',**kwargs):
pass
def i(self,*extras):
pass
def j(self,*extras,food='spam'):
pass
def k(self,*extras,**kwargs):
pass
def l(self,*extras,food='spam',**kwargs):
pass
def m(self,food='spam'):
pass
def n(self,food='spam',**kwargs):
pass
def o(self,**kwargs):
pass
def dynamic_invoke(obj,name,parameters):
action = getattr(obj,name)
spec = inspect.getfullargspec(action)
used = []
args = ()
kwargs = {}
for a in spec.args[1:]:
# skip the "self" argument since we are bound to a class
args += (parameters[a], )
used.append(a)
if spec.varargs:
args += tuple(parameters[spec.varargs])
used.append(spec.varargs)
for kw in spec.kwonlyargs:
try:
kwargs[kw] = parameters[kw]
used.append(kw)
except KeyError:
pass
# pass remaining parameters to kwargs, if allowed
if spec.varkw:
for k,v in parameters.items():
if k not in used:
kwargs[k] = v
return action(*args,**kwargs)
me = MyClass()
params = {
'foo':'bar',
'extras':['one','two','three','four'],
'food':'eggs',
'parrot':'blue'
}
dynamic_invoke(me,'a',params)
dynamic_invoke(me,'b',params)
dynamic_invoke(me,'c',params)
dynamic_invoke(me,'d',params)
dynamic_invoke(me,'e',params)
dynamic_invoke(me,'f',params)
dynamic_invoke(me,'g',params)
dynamic_invoke(me,'h',params)
dynamic_invoke(me,'i',params)
dynamic_invoke(me,'j',params)
dynamic_invoke(me,'k',params)
dynamic_invoke(me,'l',params)
dynamic_invoke(me,'m',params)
dynamic_invoke(me,'n',params)
dynamic_invoke(me,'o',params)
print('done!')
action(**command['parameters'])
@falsetru因为*args
args=command['parameters'].pop('args',None),所以这并不容易;操作(**命令['parameters'],*args)