Visual Studio Code: How debug Python script with arguments

Question

I'm using Visual Studio Code with the inbuilt Debugger in order to debug a Python script.

Following this guide, I set up the argument in the launch.json file:

Enter image description here

But when I press on Debug, it says that my argument is not recognized my shell, or rather the argparser, says:

error: unrecognized arguments: --city Auckland

Enter image description here

As Visual Studio Code is using PowerShell, let's execute the same file with the same argument:

Enter image description here

So: the same file, same path, and same argument. In the terminal it is working, but not in Visual Studio Code's Debugger.

Where am I wrong?

• Chunde Huang: In Visual Studio, you can pass multiple parameter as convenient and natural way: --trail=0 --g=0 --V="HO" --save_interval=10 --verbose=True I just do not know why they will not support this in Visual Studio Code. To list arguments one by one is cumbersome and a bit silly. They just pass the arguments string to the Python parser, and things can be done easily.
• Raaka: None of the solutions below worked for me, even after restarting and spending a hour with this! Anyone else has some recommendation? This was working a few months ago for me.

Answer 1

I think the --City and Auckland are used as a single argument. Maybe try separating them like so...

Single argument

"args": ["--city","Auckland"]

Multiple arguments and multiple values

Such as:

--key1 value1 value2 --key2 value3 value4

Just put them into the args list one by one in sequence:

"args": ["--key1", "value1", "value2", "--key2", "value3", "value4"]

• Johannes: What if I have several arguments, like --city Auckland --year 2000?
• niid: Then you do it like "args: ["--city", "Auckland", "--year", "2000"]
• oli-ver: Did someone get nargs to run? args: ["--my-n-args", "4 5"] does not work: error: argument -m/--my-n-args: invalid int value: '4 5' Edit: Found it myself: args: ["--my-n-args", "4", "5"]
• konstantin: How can I do the same if I do not have any key? I would like to run something like my_program.py train. How can I add the argument "train" that is without any key?
• Rob Fisher: @konstantin that would be args: ["train"] Arguments are just passed to your program by the shell as an array of strings, and here you are defining an array of strings in json format. The Python sys module presents these as a list of strings.

Answer 2

I also noticed that if you run the script by clicking on the debug button that looks like this enter image description here, then the arguments are not passed. However, using Run -> Start Debugging (or its shortcut F5) passed the arguments successfully.

• Edson Manoel: @Sourya Dey Is there any workaround to fix that and make it get the arguments from the Debug button?
• Sourya Dey: @EdsonManoel: Not that I know of. But you can press the Debug button on the left sidebar to make the Debug pane show on the left. You can then click on the green |> button (which usually says "Python: Current File"), and the script will run in debug mode with arguments.
• Ahmad Anis: 2023 and this bug is still there.
• GaetaWoo: For seekers, the issue and resolution is here: github.com/microsoft/vscode-python/issues/18199

Answer 3

If clicking the "Debug python file" doesn't pass the arguments then add "purpose": ["debug-in-terminal"] in the launch.json file

{"version": "0.2.0",
 "configurations": [
 {
 "name": "Python: Current File",
 "type": "python",
 "request": "launch",
 "program": "${file}",
 "console": "integratedTerminal",
 "justMyCode": true,
 "args": ["--experimentName", "Debugging"],
 "purpose": ["debug-in-terminal"]
 }
 ]
}

• Austin T: FWIW in 2023 I couldn't get these arguments to pass correctly until I used that esoteric "purpose" value in my launch.json
• Vincent Yin: That's it! I spent hours following the docs to the T at code.visualstudio.com/docs/python/debugging to no avail until I came upon your solution. Thank you! Is this a recent thing in VS Code -- how come other "solutions" under this question don't need to do that? Also, as @ingernet answered below, restarting VS Code (without adding that purpose attribute) also worked. This is got to be a bug in VS Code.
• David Boreham: Also FWIW as of August 2023 this bug appears to have been fixed, at least for me running the latest VSCode.
• Étienne: @DavidBoreham so the "purpose" key is not needed any more?
• hsl: @Étienne I'm using the latest VSCode and I still need to provide the purpose key

Answer 4

--key1 value1 value2 --key2 value3 value4

can be passed as

"args": ["--key1=value1", "value2", "--key2=value3", "value4"]

_{(Combining the two answers by Pawan Kumar and Chunde Huang.)}

Answer 5

Nobody has mentioned this yet, so I thought I'd offer a suggestion that may save you some minutes and certainly some sanity. I set up my launch.json file with an args array, but I couldn't get my args to show up in the terminal when I ran the debugger.

All I had to do was quit and restart VS Code for some reason. Then it worked like a champ.

Answer 6

File launch.json in the Python project folder path .vscode, tested in Visual Studio Code F5.

{
 // Use IntelliSense to learn about possible attributes.
 // Hover to view descriptions of existing attributes.
 // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
 "version": "0.2.0",
 "configurations": [
 {
 "name": "Python: Current File",
 "type": "python",
 "request": "launch",
 "program": "${file}",
 "console": "integratedTerminal",
 "args": ["c", "pwd"],
 }
 ]
}

Answer 7

Don't forget: Once you edit the launch.json file, CLICK OFF IT, back to the py file you want to debug, THEN hit the debug button! Otherwise, it will try to debug itself! (?)

Answer 8

Combination of flags and arguments

python3 program.py --flag1 --flag2 --arg1=value1 --arg2=value2

launch.json:

"args": ["--flag1", "--flag2", "--arg1", "value1", "--arg2", "value2"]

Answer 9

There's one answer that is missing here yet.

There are two ways arguments will be passed:

1. Wrapped in a string OR, equivalent, with escaped spaces:

   • "--city Auckland" OR --city\ Auckland

   You will get this result when you use a list "args": ["--city Auckland"]

---

2. As two separated arguments with an unescaped space

   • --city Aucklang

   When you use only one string: "args": "--city Auckland" or as other answers state a list with multiple elements for each word.

---

For example, for a prompt to insert multiple arguments from a popup use

• "args": "{command:pickArgs}"

• Joe Lau: It helps when I try to debug in VS code with multiple args. Supplement docs for {command:pickArgs} in code.visualstudio.com/docs/python/debugging#_args. The default launch.json generated Python Debugger: Current File with Arguments using "args": [ "${command:pickArgs}" ] . I changed it to "args": "{command:pickArgs}".

Answer 10

Make sure that the launch.json file is selected as the active debug configuration in Visual Studio Code, follow these steps:

1. Open the Visual Studio Code editor and navigate to the Debug view by clicking on the Debug icon in the left-hand sidebar or by pressing Ctrl+Shift+D (Windows/Linux) or Cmd+Shift+D (macOS).
2. In the Debug view, click on the "Run" button to start the debugger.
3. If you have multiple debug configurations defined in your launch.json file, you will be prompted to select the one you want to use. Select the appropriate configuration from the dropdown menu.
4. Once you have selected the debug configuration, the debugger will start and your code will be executed according to the settings in the launch.json file.

Answer 11

You can avoid any configuration and just add the command line arguments to your code temporarily, bit dirty but very practical:

import sys
if __name__ == "__main__":
 sys.argv = [__file__, 'first-arg', 'second-arg', 'third-arg']
 print('arguments:', sys.argv)