Your intent is wrong in python's grammar. Because within your code, the variables range are scoped within the function. So, when you do your imports, you're creating a bunch of variables within the econometrics function range, and thus your variables are only in reach within that function.
So, let's take a simpler example:
>>> def foobar():
... a = 1
... b = 2
...
>>> foobar()
>>> a
NameError: name 'a' is not defined
here a and b only exist within foobar's function scope, so it's out of scope at the main scope.
To do what you want, the way you want it, you should declare your variable as belonging to the global scope:
def econometrics():
global pd, np, smf, sm, plt
print("Econometrics is starting")
import pandas as pd
import numpy as np
import statsmodels.formula.api as smf
import statsmodels.api as sm
import matplotlib.pyplot as plt
print("Econometrics is started")
econometrics()
So to get back to the foobar example:
>>> def foobar():
... global a, b
... a = 1
... b = 2
...
>>> foobar()
>>> a
1
>>> b
2
Though, I do not really like that way of doing things, as it's doing things implicitely. Considering you have a python module with just the econometrics function defined, people reading the following code:
from econometrics import econometrics
econometrics()
plt.something()
wouldn't necessary understand that plt has been made available through the econometrics function call. Adding a comment would help, but still is an unnecessary extra step.
Generally speaking, doing globals within any language is wrong, and there's most of the time always a better way to do it. Within the "Zen of python", it is stated that "Explicit is better than implicit", so I believe a more elegant way would be to create a module that does the import, and then you'd import what you need from the module:
econometrics.py:
import pandas as pd
import numpy as np
import statsmodels.formula.api as smf
import statsmodels.api as sm
import matplotlib.pyplot as plt
and in your code you'd then import only what you need:
from econometrics import pd, plt
plt.something()
which would be much more elegant and explicit! Then, you'd just have to drop that file in any projects you need your mathematics modules to have all your beloved modules that need - and only them - available in your code!
Then as a step further, you could define your own python module, with a full blown setup.py, and with your econometrics.py file being a __init__.py in the econometrics package directory, to then have it installed as a python package through:
python setup.py install
at the root of your sources. So then any code you work out can be using econometrics as a python package. You might even consider making it a package on pypi!
HTH
