Is a string formatter that pulls variables from its calling scope bad practice?

Question

I have some code that does an awful lot of string formatting, Often, I end up with code along the lines of:

\"...\".format(x=x, y=y, z=z, foo=foo, ...)
         


        

Answer 1

In the inspect module, currentframe is defined like this:

if hasattr(sys, '_getframe'):
    currentframe = sys._getframe
else:
    currentframe = lambda _=None: None

So unless sys has a _getframe attribute, the interpolate function will not work.

The docs for sys._getframe say:

CPython implementation detail: This function should be used for internal and specialized purposes only. It is not guaranteed to exist in all implementations of Python.

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Writing

"{x}, {y}, {z}".format(**vars())

in the function body is not that much longer than

interpolate("{x}, {y}, {z}")

and your code will be more portable.