how to debug python in visual studio - python

I recently started working in python with visual studio and I have 2 questions please:
Is there some kind of special configuration that you have to perform in order to be able to debug python code? Was I supposed to install something or did VS come this way?
Suppose im in a decoding session, inside a function that's declared in the scope of some class. Can I view the values of the class variables defined in the init? If so, how? I tried to write "self.someField" in the watch window but it didn't work.
Thanks you!

You could debug your python code like general debugging steps in VS, of course, it also has different settings or Environment options.
If you want to get much more detailed information, please see this document here:
Debugging your Python code
In addition, one thread for one issue, for the second issue:
2.Suppose im in a decoding session, inside a function that's declared in the scope of some class. Can I view the values of the class
variables defined in the init? If so, how? I tried to write
"self.someField" in the watch window but it didn't work.
If possible, I suggest you open a new case for this new issue, you could also share your main code, so other community members could really repro this issue in their side.

Related

Where do I see existing variables after executing my script?

Where do I see existing variables after executing my script? I have become accustomed to having a panel to see what existing variables I have and what their types and contents are in MATLAB and Spyder; how is this done in VSCode for Python?
During debugging, you can inspect all available variables on the left side of the screen as shown in the following screenshot (although after debugging they disappear)

Get Autocomplete for a special variable in python

I am using vs code for python scripts. These scripts run on the server only.
The server however, passes certain variables to the script while executing the script.
e.g mbo is always passed in it. mbo is special keyword which corresponds to a some class.
Sample mbo.py
class Mbo:
def getString(column: str)-> str:
return 'ABC'
def setString(columnName: str)-> None:
# do something with columnName.
Goal:
In my project in any python file whenever the user types mbo followed by a . vs code should show autoscomplete for .getString() and .setString() without importing this class as it is passed to the script by server.
I can try to write an extension for vs code to add this feature.
Here, I am stuck that what kind of extension is needed here. A LSP? I don't want to loose the feature of the existing python LSP for python.
Can any one proficient with vs code extension API guide me in right direction.
Note: I cannot import this Mbo class just for autocompletion in vscode because I import it. Then I run the same script on server. The server throws errors about the file.
You could try making the imports conditional:
try:
mbo
except NameError:
import mbo
That might be enough to make one of the two IntelliSense engines in the Python extension work.
Otherwise you are looking at your own extension. LSP is obviously the best option but there's also the classic style of registering classes. The VS Code docs have the details. But you are still probably going to clash with the Python extension as both it and your extension will be registered to work with Python files.

PyCharm: Storing variables in memory to be able to run code from a "checkpoint"

I've been searching everywhere for an answer to this but to no avail. I want to be able to run my code and have the variables stored in memory so that I can perhaps set a "checkpoint" which I can run from in the future. The reason is that I have a fairly expensive function that takes some time to compute (as well as user input) and it would be nice if I didn't have to wait for it to finish every time I run after I change something downstream.
I'm sure a feature like this exists in PyCharm but I have no idea what it's called and the documentation isn't very clear to me at my level of experience. It would save me a lot of time if someone could point me in the right direction.
Turns out this is (more or less) possible by using the PyCharm console. I guess I should have realized this earlier because it seems so simple now (though I've never used a console in my life so I guess I should learn).
Anyway, the console lets you run blocks of your code presuming the required variables, functions, libraries, etc... have been specified beforehand. You can actually highlight a block of your code in the PyCharm editor, right click and select "Run in console" to execute it.
This feature is not implement in Pycharm (see pycharm forum) but seems implemented in Spyder.

How do I embed an Ipython Notebook in an iframe (new)

I have successfully achieved this using the method documented at Run IPython Notebook in Iframe from another Domain . However, this required editing the user config file. I was really hoping to be able to set this up via the command-line instead (for reasons).
http://ipython.org/ipython-doc/1/config/overview.html indicates that configuration via the command line is possible. However, all the examples are for simple true/false value assignment. To set the server up to allow embedding, it is necessary to set a value inside a dictionary. I can't work out how to pass a dictionary in through the command-line.
Another acceptable option would be a configuration overrides file.
Some people will wonder -- why all this trouble!?!
First of all, this isn't for production. I'm trying to support non-developers by writing a web-based application which integrates Ipython notebooks within it using iframes. Despite being on the same machine, it appears that the different port number used is enough to mean that I can't do simple iframe embedding without setting the x-frame insecurity bit.
Being able to do this via the command line lets me set the behaviour in the launch script rather than having to bundle a special configuration file inside my app, and also write an installer.
I really hope I've make the question clear enough! Thanks for any and all suggestions and help!
Looking over the IPython source for the loaders, it seems like it will execute whatever python code you put on the right hand side. I've not tested it, but based on the link you provided, you can probably pass something like
--NotebookApp.webapp_settings=dict('headers'=dict('X-Frame-Options'='ALLOW-FROM https://example.com/'))

Code completion not giving recommendations

Say I'm working with the 'requests' Python library.
req = requests.get("http://google.com")
Now after this, if I type req., I'm supposed to get a list of all methods I can access. But for some reason I don't, even if I manually press Ctrl+Space.
If I try this in iPython, I get autocomplete recommendations. Even if I try it via the built in Python console in PyCharm, I get recommendations.
Why's this happening?
As Python is a dynamically typed language, you need to ensure it can work out what type things are, and inspect on the libraries on your system correctly. Try to make sure it's obvious what type the object is in your code.
One good way as of PyCharm 2.7 (back when versions were numbers) is to enable runtime type detection - PyCharm hooks into your program while it runs (while debugging), and checks the types of variables as they are used.
You can enable this by going to settings, going to the "Build, Execution, Deployment" section and then the "Python Debugger" subsection and enabling "Collect run-time types information for code insight".
Obviously it is worth noting that this isn't perfect - if you make changes, this won't be updated til the code is executed, and it can only tell you about values it has seen - other code paths you haven't tried could set other types.
You can also 'tell' PyCharm by using Epydoc or Sphinx style docstrings that contain information about parameter and return value types. PyCharm will use these to improve it's inspections.
Python also gained support for function annotations as of Python 3. These can be used for type hints as per PEP 484. See the typing module for more. This is more formal, so it can also be used for tools like mypy which a type checker that can programmatically check these types for consistency, giving Python a TypeScript-style optional static typing.
Python is a dynamically typed language, which means that the "get" function does not declare its return type. When you're entering code in IPython or in the PyCharm console, the code is actually being executed, and it's possible to inspect the object instance in the running interpreter and to get the list of its methods. When you're entering code in PyCharm or in any other Python IDE, it is not executed, and it's only possible to use static analysis to infer the return type of the method. This is not possible in all cases.
PyCharm has no idea what the dict contains if you fill it dynamically. So you have to hint PyCharm about the keys of dict beforehand. Prodict does exactly this to hint PyCharm, so you get code completion.
First, if you want to be able to access the response object, then you have to get a json response and convert it to dict. That's achieved with .json() method of requests like this:
response = requests.get("https://some.restservice.com/user/1").json()
OK, we loaded it to a dict object, now you can access keys with bracket syntax:
print(response['name'])
Since you ask for auto code completion, you certainly need to hint PyCharm about the keys of dict. If you already know the respone schema, you can use Prodict to hint PyCharm:
class Response(Prodict):
name: str
price: float
response_dict = requests.get("https://some.restservice.com/user/1").json()
response = Response.from_dict(response_dict)
print(response.name)
print(response.price)
In the above code, both name and price attributes are auto-complated.
If you don't know the schema of the response, then you can still use dot-notation to access dict attributes like this:
response_dict = requests.get("https://some.restservice.com/user/1").json()
response = Prodict.from_dict(response_dict)
print(response.name)
But code-completion will not be available since PyCharm can't know what the schema is.
What's more is, Prodict class is derived directly from dict, so you can use it as dict too.
This is the screenshot from Prodict repo that illustrates code completion:
Disclaimer: I am the author of Prodict.
if will just detect methods or variables and... with write some part of it:
File->Setting -> Editor -> General -> Code Completion
in top of opened window , unCheck [ Mach Case ]
It's an old question but probably all the provided answers missed the mark by a margin as wide as Sun's distance to Betelgeuse (none of the answers is accepted and #user1265125 is an active guy with 8 yrs here and more cred than me).
As it happens, I've just had exactly the same problem as OP and the solution was:
A NON-ASCII CHAR SOMEWHERE IN THE PROJECT'S FOLDER PATH
Seriously, PyCharm devs...[doubleFacepalm]
In my case the solution is to reset the settings, everething else wasn`t working for me.
"From the main menu, select File | Manage IDE Settings | Restore Default Settings.Alternatively, press Shift twice and type Restore default settings."
I had a similar problem. Only functions I had already used were suggested and only as plain text and not recognised as methods.
What fixed that for me was deleting the /.idea folder in the project directory. (Afterwards you will have to set your run configurations again)
With the latest version update to 2022.2, even auto-complete stopped working for me. After quite a bit of reading articles, I just found the https://youtrack.jetbrains.com/issue/PY-50489 issue which was the root problem. The old plugins were pending update, after that, the code completion issue was fixed.
So, try and check if you are facing the same problem, if the plugins are up to date in Settings —> Plugins.

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