Modular•16mo ago

How do I open files to read/write in Mojo?

I want to do the equivalent of the following Python code:

with open(file.txt, 'r') as file:
  x = file.read()

with open(file.txt, 'r') as file:
  x = file.read()

How can I do this?

23 Replies

sa-code•16mo ago

You can use @lukas 's lib for now: https://github.com/lsh/shims

GitHub

GitHub - lsh/shims: Utils for mojo projects

Utils for mojo projects. Contribute to lsh/shims development by creating an account on GitHub.

bhavnicksmOP•16mo ago

@sa-code How do you use this repository to read files? The read has code but there's no example usage, so it's hard to understand

lukas•16mo ago

The read code has an example at the top of the file

bhavnicksmOP•16mo ago

Thanks, will try it out!

Tenesis•16mo ago

@lukas can you give an example on how to write files as well? Thanks a lot!

lukas•16mo ago

I haven’t written a wrapper for that yet I haven’t had a need, but will probably get around to it soon

Tenesis•16mo ago

I see. So as far as we know there's currently no way to write to file in Mojo yet?

lukas•16mo ago

You can call the CAPIs i.e write your own fwrite wrapper in the same way I did an fread wrapper

Tenesis•16mo ago

Cool, I can try that out Thanks!

Tenesis•16mo ago

Here we go" https://github.com/ShuzhaoFeng/mojo-minwa

GitHub

GitHub - ShuzhaoFeng/mojo-minwa: The minimal library you need to wr...

The minimal library you need to write / append file in Mojo - GitHub - ShuzhaoFeng/mojo-minwa: The minimal library you need to write / append file in Mojo

lukas•16mo ago

Nice 🙂 @Tenesis thought I'd ping you that I've since added a buffered writer

Tenesis•15mo ago

Awesome. 🥳 Thanks Lukas

lukas•15mo ago

By the way there’s now the open method available, but I’m pretty sure it’s not buffered yet, so its use will depend on what you’re doing

Elaid Tebabkha•15mo ago

It is simple with the version 0.4.0 , you have to see the documention of this version 🙏:mojo: :python:

bhavnicksmOP•15mo ago

Thanks @Elaid Tebabkha! 🩵 Will check it out now

ModularBot•15mo ago

Congrats @bhavnicksm, you just advanced to level 1!

bhavnicksmOP•15mo ago

@Elaid Tebabkha @lukas I was trying out the open method yesterday and I am facing issues with both reading and writing to a file. Mojo v0.4 doesn't seem to be able to parse it properly. Here's a screenshot of what I faced, and the code I was trying to execute

Balderdash•15mo ago

from pathlib.path import cwd
from pathlib.path import Path

from python import Python

fn main() raises:
    let currentPath = cwd()
    let file = currentPath/"my_file.txt"
    
    with open(file, "w") as f:
        f.write("Hello, world!")

    with open(file, "r") as f:
        print(f.read())

    let os = Python.import_module("os")
    os.remove(file.path)

from pathlib.path import cwd
from pathlib.path import Path

from python import Python

fn main() raises:
    let currentPath = cwd()
    let file = currentPath/"my_file.txt"
    
    with open(file, "w") as f:
        f.write("Hello, world!")

    with open(file, "r") as f:
        print(f.read())

    let os = Python.import_module("os")
    os.remove(file.path)

It's a working example .. you may add raises to your main function ?

bhavnicksmOP•15mo ago

@Balderdash Oh with raises it seems to work! Thanks Do you know why this works though? I don’t understand this properly

Balderdash•15mo ago

When you call a function, which throws an exception you need either to catch and handle it or define in your function by using key 'raises' its given to its caller to handle it.

Elaid Tebabkha•15mo ago

Or use try except finally.🙏

bhavnicksmOP•15mo ago

Yes, try-except also seems to work

Elaid Tebabkha•15mo ago

You can also write The code in python an import it inside the Mojo code like a PythonObject and execute the mojo code .

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How do I open files to read/write in Mojo?

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