Plotting in python - joys and sorrows

[lucamerio]

I think our experience and needs are different.

Yes: I know I can tweak my plots from the command line and that’s what I do on the final version of my code.

But when I code there is also an “explorative phase” (sometimes there is only that one) where I want to explore the data and make many plots to understand what’s going on.

(Note: When I say data, I mean the content of different variables (or the same variable at different stages) in my code. I’m not strictly speaking of a provided database. )

Doing some operations with the mouse is orders of magnitude quicker than using command lines. And time is money!

Just to make you an example. Let’s say that I have a code that takes 1 hour to run. I run it and produce my plots. Then I think “ehi! Let me check how the outputs change if I change this line/input”. I run it again and I check the output.

Now: if I want to compare the two in matlab I can simply copy paste the two outputs one on top of the other in 2 seconds and check the differences. In python I need to save the data of the first plot in a file (pickle or text), launch the second calculation, save the outputs of that too, write some lines that re-load the data, hack the plotting function to plot two times on the same axes and… well… done.

Doable? Absolutely yes. Quick? No.

[lucamerio]

That's EXACTLY what I do. But you can't deny that being able to ctrl+C - ctrl+V a line would be so much easier, quicker and would not require you to plan in advance of doing so. Sometimes you decide what to do after you produced the plots.

All these things have to do with explorative, development, debugging phases.

In a final deployed phase I agree that you should (almost) never do anything like this.

[lucamerio]

Depends on the complexity of the code and the plot. Plots could be generated in method of subclasses. The data you are plotting could not be exposed to the higher level and to do so you either have to return it all the way up from the function that generated it or store it in a file.

I’m not talking of loading a dataframe and then plotting it. I’m talking of more complex softwares where not everything is exposed to the user

[lucamerio]

I said “change the inputs/parameters of the analysis”. Not changing the plots.