Importing Numpy into functions

Question

I do not know the right way to import modules.

I have a main file which initializes the code, does some preliminary calculations etc. I also have 5 functions f1, f2, ... f5. The main code and all functions need Numpy.

If I define all functions in the main file, the code runs fine. (Importing with : import numpy as np)

If I put the functions in a separate file, I get an error:
Error : Global name 'linalg' is not defined.

What is the right way to import modules such that the functions f1 - f5 can access the Numpy functionality?

import numpy at the beginning of every file, if it's been imported once, it won't import again, but you will have the namespace to work with. — Josiah
– Josiah, Commented Aug 3, 2012 at 3:42

Balthazar Rouberol · Accepted Answer · 2012-08-03 07:11:43Z

5

As other answers say, you need to import numpy into each file where you call a Numpy function. However you don't need to import it into the main module if you're not using it in the main module. Here's a simple example. Imagine you have a file with your function in it called myFunc.py myFunc.py:

import numpy as np

def f1(a):  # a is a numpy multidimensional array
    z = np.array(a)
    flat = z.ravel()
    flat = flat.tolist()

    return flat

Then in your main file you can do something like this

import myFunc as mf

mf.f1([[4,67,8],[7,9,7]])

Your output will be:

[4, 67, 8, 7, 9, 7]

So you pass a list to your function, convert it to a numpy array in your function, then return the answer as a list. If you return a numpy array you'll get an error.

edited Aug 3, 2012 at 7:11

Balthazar Rouberol

7,2302 gold badges37 silver badges41 bronze badges

answered Aug 3, 2012 at 4:17

emhart

8045 silver badges9 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

BrenBarn · Accepted Answer · 2012-08-03 03:42:22Z

1

You have to import modules in every file in which you use them. Does that answer your question?

answered Aug 3, 2012 at 3:42

BrenBarn

253k39 gold badges421 silver badges392 bronze badges

1 Comment

Garnet Over a year ago

Yes. I thought that was repetitious and the right way was to just import them once. Thanks.

Collectives™ on Stack Overflow

Importing Numpy into functions

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related