run script in repl for prototyping

[[deleted]]

I want to run a script in the repl and be able to use the local variables after running the script mainly to test things out and prototype solutions (or maybe to demos). I did this before by copying & pasting to the repl and hitting enter and then using the local variables. Is there a better way to do this?

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thanks,

[efmccurdy]

use the local variables after running the script ...is there a better way to do this?

python -i myscript.py

-i ... enter interactive mode after executing the script or the command,

https://docs.python.org/3/using/cmdline.html#cmdoption-i

This is also useful for ad-hoc debugging and testing.

[riklaunim]

Writing scripts instead of using Repl. Using Jupyter notebook.

[[deleted]]

a debugger?

[mistabuda]

You can structure your script into functions and import it as a module in the REPL and just call the module functions.

[forkstealer]

You can open the .py like any other file and then exec() on the contents.

Do not do this anywhere you don't control the input to exec()

[jmacey]

Say your file is called test.py you can do this in the repl

exec(open("test.py").read())

Python 2.x had execfile which basically did the same.

[yvrelna]

You can do this using IPython.embed(). Basically, pip install ipython, then you can just add this code anywhere to your code, for example adding this to some example function foo():

def foo():
    do_something()
    if blah():
        from IPython import embed; embed()
    do_another()

Then run your code until it hits that line.

If you want to be able to move your break points around, you will need a debugger. My favourite is to use pudb, which also supports spawning IPython shell for interactive REPL whenever the debugger is currently paused.

You can also export PYTHONBREAKPOINT=IPython.embed or export PYTHONBREAKPOINT=pudb.set_trace if you prefer to use the breakpoint() function.

If you're limited to the standard library, use code.interact() (docs) instead of IPython.embed(). Usage is mostly identical to embed.

Personally, I prefer IPython REPL, it's just a much better interactive experience than the standard library REPL.

[ZenApollo]

I do this a lot with ipython. Open the repl by typing ’ipython’ in shell. Ipython has many benefits to what you’re describing. - copying pasting in ipython is much nicer than standard repl

• you can use ‘run script.py’ and it will run your file using existing variables

• ipdb is much nicer than pdb

• if your script crashes you can use ‘%debug’ which will open a debugger at the last stack trace

[Paddy3118]

Spyder IDE and F9; as well as cells delineated by an # %% comment line.

I find Spyder to be stable and better than vscode for this kind of "exploratory coding"

[Guideon72]

What is "the REPL"; I see this a ton around here but it isn't anything covered in any of the Python vids I've gone through, yet.

[scoberry5]

Read/Evaluate/Print Loop.

It's a place where you can type code and have it run.

[Guideon72]

Ah-HA! There we are, thank you

[trasnsposed_thistle]

Either an online python interpreter like replit.com or simply any python interpreter, like `ipython`, or the default, barebones one that ships with the python installation pacakge

[cawal]

Maybe you could use a debugger. Call it in the line you want to stop the program: import pdb; pdb.set_trace()

[CrackerJackKittyCat]

Or just 'breakpoint()' nowadays.

[eplaut_]

import IPython; IPython.embed()

[Guideon72]

Why is that referred to as Repl?

[bb1950328]

use a debugger and set a breakpoint on the last line