Get rid of checking len(list) and call functions with/without args-CodePudding

I've got a list, smth like this ['func1', parm1] or ['func2']

In some cases, there is no second element in the list. The method supposed to call has **kwargs argument, like def func1(self, **kwargs)

My current code is

cmd = matrix[i][0]
value = None
len_matrix = len(matrix[i])
if len_matrix > 1:
    value = matrix[i][1]
method = getattr(obj, cmd)
if len_matrix > 1:
    method(x=value)
else:
    method()

CodePudding user response：

You could use pop(0) on the list to extract the first parameter (the function name). This mutates the list so it will just contain the arguments (if any).

def example(a="a", b="b"):
    return a, b


cmd = ["example", "arg_a", "arg_b"]

def caller(args):
    func_name = args.pop(0)
    func = globals()[func_name]
    return func(*args)

caller(cmd)

CodePudding user response：

I don't think it will improve readability, but you can achieve this by creating your kwargs dictionary dynamically.

getattr(obj, matrix[i][0])(**({"x": matrix[i][1]} if len(matrix[i]) > 1 else {}))

If you possibly have more arguments you could extend that more or less easily:

arg_names = "xyzabc"
getattr(obj, matrix[i][0])(**{
    arg_names[it]: val for it, val in enumerate(matrix[i][1:])
})

Obviously you could also use arg_names[it - 1]: matrix[i][it] for it in range(1, len(matrix[i]))

Hope that helped.