DOC: add Numpy import to examples

[BassCoder2808]

Reference issue
#16759

What does this implement/fix?
Added import numpy as np to docstring examples in every file as per the script https://gist.github.com/WarrenWeckesser/f81e1d6453a639c745da50746d7078fb

Additional information

[melissawm]

These all look fine to me. I haven't looked into the files to see if there are any other examples that need the import line, but I did verify that all of those listed here actually use numpy for the example.

[melissawm]

Minor nit: maybe we want to keep np.fft here instead of importing again? Not sure if that would be too verbose for the code, though.

[melissawm]

Same comment as above: might as well have one import?

[melissawm]

Again, might be simplified.

[WarrenWeckesser]

In cases where the example has code like this

    >>> from numpy.random import default_rng
    [...]
    >>> rng = default_rng()

I agree with @melissawm's suggestion to adjust to code to have just one numpy import. The code would become

    >>> import numpy as np
    [...]
    >>> rng = np.random.default_rng()

This is consistent with most other uses of default_rng throughout the SciPy examples.

The one other case like this involves scipy.signal.max_len_seq, which has the import

    from numpy.fft import fft, ifft, fftshift, fftfreq

I think we can leave that as is in this pull request. In a separate pull request, we could change that to import from scipy.fft instead of numpy.fft.

[WarrenWeckesser]

I think you missed a few fixes in the last update. I have some changes requested, otherwise this looks good. There are a few places where the import of numpy is not at the beginning, but that is still a topic of discussion, so not a problem.

[WarrenWeckesser]

There is one change needed. I'll push that, let the tests run again, and merge if that goes well.

Requested changes have been made.

[WarrenWeckesser]

The 3.11-dev job installs numpy from the main development branch. The failures are the result of numpy/numpy#22385, and not related to this pull request.

[WarrenWeckesser]

Merged. Thanks @BassCoder2808!