python: **kwargs to variables

Question

In a function def test(**params), how do I use the keys of **params to create variables named by kwargs.keys() with values kwargs.values() that I can use inside of my function test?

Answer 1

EDIT: This approach doesn't work in most circumstances. I tested it in IPython where it does work in the outer context.

You should just use the kwargs __get__ lookup. It is bad practice to do this,

~~but if you insist on creating these variables you can do: locals().update(kwargs). Doing this makes this code valid:~~

def foo(**kwargs):
   locals().update(kwargs)
   return a + 3

print(foo(a=3))

~~will output 6~~

will output NameError: name 'a' is not defined

---

EDIT: This works

I'm actually quite surprised that updating locals doesn't work in the standard interpreter. I also found that eval doesn't work either. I've been using tricks like this in IPython for years. Looking at Modifying locals in Python it seems like you used to be able to do this in Python 2 using exec, but its no longer valid in Python 3 (which is probably a good thing).

However, I have found a hack that I believe works. Again, please don't do this in practice.

def foo(**kwargs):
    foo.__globals__.update(kwargs)
    return a + 3

print(foo(a=3))