Examples missing import numpy as np?

Hi

a bunch of examples seem to be missing import numpy as np. At least for me they throw NameError: name 'np' is not defined.

Following examples seem to be missing import numpy as np (non exhaustive):

• scipy.signal.spectrogram
• scipy.signal.periodogram
• scipy.signal.welch

scipy.__version__ gives 1.4.1. However, the examples seem to be the same in the current master.

Maybe I am missing something? Any help is appreciated! Thanks 😃

[stefanv]

I don’t have a horse in this race, but I wanted to mention an alternative that came up on https://github.com/networkx/networkx/issues/5720

We could ask IPython/Jupyter whether they could detect common missing names and give an error message after a NameError with some guidance, such as:

Hint: it looks like you are missing an import; to use SciPy, try `import scipy as sp` first

This is a best-of-both-worlds type scenario, where we don’t need to repeat the same imports over and over in the docstrings, but users get helpful feedback for common package imports (np, sp, plt, pd, nx, etc).

[andyfaff]

Some docstrings have multiple examples, but these are often interspersed with lots of text. Should a numpy import happen once in a docstring, or with each example (as previous comments suggest)? The latter is bloat-worthy.

numpy is ubiquitous, so knowing what np.sum means without the import being included in a docstring doesn’t seem like an egregious act. Even then it’s only a websearch away. A single websearch is small fry compared to ‘ugliness’ caused by adding an explicit numpy import.

Besides, there are inline code snippets in multiple places that implicitly use np: np.std(pop) <= atol + tol * np.abs(np.mean(population_energies)) is present in the docstring, do they deserve an import?

In a typical interpreter session (Python/IPython) you only need to do the import once (18 characters worth), and it lasts for the duration of the session. I would argue that the cost of typing that is miniscule compared to the cost incurred by adding the numpy import to every example.