ENH: Initilize Print Options from Environment Variables

[daskol]

Proposed new feature or change:

At the moment, print options are initialized with default options and can be changed with either numpy.set_printoptions function or numpy.printoptions context manager. Sometimes it is not very convenient to modify a code with mentioned above function to display arrays in more readable way.

It would be great to initialize print options from environment variables prefixed with NUMPY_PRINTOPTION_ (e.g. precision print option should be initialized from NUMPY_PRINTOPTION_PRECISION envvar).

NUMPY_PRINTOPTION_LINEWIDTH=120 python my-fance-solver.py

[LeonaTaric]

good idea

[daskol]

good idea

Thanks. I am still waiting for triage.

[mattip]

Environment variables seems like a bad fit for this. Perhaps a different mechanism to parse global state options would be better: some kind of config file like matplotlib has?

Sometimes it is not very convenient to modify a code with mentioned above function to display arrays in more readable way.

Could you describe your use case a bit more? Is it really so hard to add a snippet to set the printoptions at startup?

[daskol]

Environment variables seems like a bad fit for this.

Why? For example, make verbosity is controlled with VERBOSE=1 envvar or Google's glog logger can be fine-tuned with GLOG_* variables. By the way, matplotlib works with envvar as well.

Could you describe your use case a bit more?

From my perspective, there are several aspects of the issue.

The first one is that line width equals 80 is a good choice in general but nowadays we have wider screens and terminals and this value should be adjusted somehow in order to print more information and use benefits of wide displays. In this case, .mpstyle-like files can be a good solution to configure basic settings. However, NumPy print options are not dynamically adjusted in case if someone resizes the terminal (e.g. GUI or TMUX).

Another one aspect is that use of np.printoptions requires source code modifications. It requires text editor which is not always available (e.g. isolated environment like docker container may not have an editor). Also, editing text is plain and simple but not simpler than just prepending with envvar on demand as follows.

NUMPY_PRINTOPTION_LINEWIDTH=160 python run-my-solver.py --opt1 --flag2 posisional3

In my opinion, envvar is a good well-known widely-used non-invasive and easy way to adjust configuration in general and printing options in particular.

[rossbar]

I agree with @mattip and am leery about environment variables, as this approach would then be subject to platform dependencies.

The next step here would be to post this proposal to the NumPy mailing list, as that's the correct forum for proposing new features.

[daskol]

this approach would then be subject to platform dependencies.

And this is okay. Envvars exist on the majority of platforms which are Linux, BSD, macOS, Windows, and even DOS. I am pretty sure that the majority of developers works on these platforms and I am not sure that Python can even be built on platforms which are not in the list (e.g. WebAssembly). The latter means that compatibility issues are reduced to existence of a special function (namely, os.getenv). In other words, Python is a compatibility layer itself.

Thank you, I'll send the proposal to the mailing list.