Assign function-local parameter to global variable with same name

Question

I have a module; say it's structured as:

algorithms
 ├─ __init__.py
 └─ algorithm.py

Inside my algorithm module, I have some global vars, and I would like to create a convenience initializer that sets them up. I would like to use the same names for the initializer's parameters as for the vars, but that leads to a conflict of local and global names. The cleanest way I can think of to implement this is:

lower = None
upper = None

def init_range(lower, upper):
   _lower = lower
   global lower
   lower = _lower

   _upper = upper
   global upper
   upper = _upper

If this were a class, (I think) I could do something like self.lower = lower. Is there a less verbose way to do what I'm doing for module-global vars? Something like algorithm.lower = lower?

EDIT: Turns out my solution doesn't work.

You don't want to hear this, but your solution doesn't work and the correct solution is to avoid globals. — Aran-Fey
– Aran-Fey, Commented Jun 2, 2018 at 8:52
You're correct, it doesn't work :( but in my case, I already use globals everywhere (this is a very minimal example), and there's no time to change that. — Phlippie Bosman
– Phlippie Bosman, Commented Jun 2, 2018 at 9:21

Aran-Fey · Accepted Answer · 2018-06-02 08:56:13Z

2

You can use the globals function to get the dictionary representing the global scope, and update it:

def init_range(lower, upper):
   globals().update(lower=lower, upper=upper)

answered Jun 2, 2018 at 8:56

Aran-Fey

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1 Comment

timgeb Over a year ago

I think this answer is better than mine, because this, which readers should be aware of.

timgeb · Accepted Answer · 2018-06-02 08:52:46Z

2

If you really insist on keeping the parameter names lower and upper (why not just new_lower, new_upper or something like that?) then you could delegate the task to an inner function with alternative variable names.

def init_range(lower, upper):
    def _init_range(_lower, _upper):
        global lower
        global upper
        lower = _lower
        upper = _upper

    _init_range(lower, upper)

Demo:

>>> lower is None, upper is None
(True, True)
>>> init_range(lower=1, upper=2)
>>> lower, upper
(1, 2)

answered Jun 2, 2018 at 8:52

timgeb

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