Convert .py scripts to marimo notebooks

[cnrrobertson]

Description

Currently marimo convert allows for .md or .ipynb filetypes to convert to notebooks. Unfortunately I've always used .py files with # %% cell delimiters like those outputted by marimo export script file.py for interactive REPL work.

Could marimo convert be extended to also take in these flattened .py files and put them into notebook form? This would make using marimo with my previous work so much easier!

Suggested solution

It seems like it could be as simple as putting some header informatio, replacing any line of # %% with @app.cell\ndef __():, and then ensuring lines are indented correctly. I've already implemented a quick script to do conversion this way.

However, this doesn't account for any variable dependence. So far, it seems like marimo figures out the dependencies when I do this conversion and run the first time, but there may be something more subtle here.

This also doesn't entirely account for other kinds of cells like # %% [markdown].

Alternative

No response

Additional context

No response

[akshayka]

However, this doesn't account for any variable dependence. So far, it seems like marimo figures out the dependencies when I do this conversion and run the first time, but there may be something more subtle here.

Yea, you're right the dependencies are just for readability. marimo can fill them in automatically.

I wonder if there's a tool that converts .py scripts to ipynb files? If so, then you could use marimo convert

[akshayka]

@cnrrobertson According to an SO post, you can use jupytext to go from .py script to ipynb: https://stackoverflow.com/a/55920098

[cnrrobertson]

Ah you're right! That works great. Thanks for the help!

I'd say this can be closed now, but I'll let you guys make the call in case this is something you'll want to include in Marimo at some point.

[mscolnick]

Yea, we can close this. @cnrrobertson if you have a small snippet that you used in your CLI, would be great to add it here for others.

[cnrrobertson]

Sure thing. Here's the quick and dirty snippet I've been using to go from script to Marimo notebook. So far it has worked pretty well:

#!/opt/homebrew/bin/python3

import sys
filename = sys.argv[1]

with open(filename, 'r') as file:
    lines = file.readlines()

new_lines = [
    "import marimo\n",
    "\n",
    # f'__generated_with = "{__version__}"',
    "app = marimo.App()\n",
    "\n",
    "\n",
    "@app.cell\n",
    "def __():\n",
]

for line in lines:
    if line[:4] == "# %%":
        new_lines.append("    return\n")
        new_lines.append("\n")
        new_lines.append("@app.cell\n")
        new_lines.append("def __():\n")
    elif "__generated_with" in line:
        continue
    elif line == "":
        continue
    elif line == "\n":
        continue
    else:
        new_lines.append("    "+line)

if "return" not in new_lines[-1]:
    new_lines.append("    return\n")

print("".join(new_lines))

Note that it cuts out blank lines.