CODEWITHSUNDEEP
pythonpython-3.xargumentsdecoratormetaclass
2Cubed
2Cubed

Reputation: 3551

How can I use a decorator to modify the type of *args?

I would like to use a @decorator to allow me to be able to access ' - '.join(args) as args, as depicted below. Is this possible, using a metaclass perhaps?

def a(*args):
    print(args)
a(1, 2, 3)
# (1, 2, 3)

@magic
def b(*args):
    print(args)
b(1, 2, 3)
# 1 - 2 - 3

Upvotes: 3

Views: 83

Answers (2)

whybull
whybull

Reputation: 51

So part of the problem is that you're using integers where you need strings, so convert them into strings and then use the join function. 

def magic(func):
    def wrapper(*args):
        return ' - '.join(map(str, args))
    return wrapper

@magic
def a(*args):
    return 'Arguments were {}.'.format(args)

print(a(1, 2, 3))

Upvotes: 0

Alex Hall
Alex Hall

Reputation: 36033

You can get close:

def magic(func):
    def wrapper(*args):
        return func(' - '.join(map(str, args)))
    return wrapper

but this prints out ('1 - 2 - 3',) because the body of b sees args as a tuple due to the *args, and I doubt a decorator can get around that. What do you expect to happen if the body is something like print(args[1])?

Upvotes: 2

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