Slides

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### 28: Python virtual environments, VSCode launch configurations, packages w/ pip and requirements.txt

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#### Outline

- [Our bug from yesterday: a Vim browser extension](#3)
- [Python virtual environments (in VSCode)](#4)
- [Setting up a launch configuration in VSCode](#5)
- [Python packages, the Python package index, and pip](#6)
- [Package dependencies at the project level, requirements.txt](#7)
- [Preview: Git (with Git bash), SourceTree, and GitHub (remote repository host)](#8)

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#### Our bug from yesterday: a Vim browser extension

- If anyone else uses Chrome Remote Desktop with Vimium active, you have been warned!

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#### Python virtual environments (in VSCode)

- Virtual environments at a high level -- sandboxing project packages so that they don;t interfere with each other
- In VSCode specifically: https://jasonmurray.org/posts/2020/vscodepythonvenv/
- In the integrated terminal, run:
  - `python -m venv .venv`
  - And then `./.venv/Scripts/activate` to activate the virtual environment

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#### Setting up a launch configuration in VSCode

- https://code.visualstudio.com/docs/python/debugging#_set-configuration-options

Example:

```json
{
    // 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
    "configurations": [
        {
            "name": "Preprocess",
            "type": "python",
            "request": "launch",
            "program": "main.py",
            "console": "integratedTerminal"
        }
    ]
}
```

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#### Python packages, the Python package index, and pip

- https://pypi.org/
- https://www.w3schools.com/python/python_pip.asp
- `pip` is a package manager for Python, just like `choco` is a package manager for Windows.

Example:

- Let's say you want to build a URL from a file path. URLs don't have spaces (conventionally), and usually follow a specific format. To get strings in a format, we can download a package and use it: https://pypi.org/project/python-slugify/

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#### Python packages, the Python package index, and pip

Let's say we had a simple program like the following

```python

import slugify

def make_url(input_string):
  return slugify.slugify(input_string)

```

You can also just import the function directly (`from slugify import slugify` = in the format of `from module_name import function_name`), and then you don't need to worry about the module name when invoking the method.

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#### Package dependencies at the project level, requirements.txt

- It's not as hard as you might think
- https://note.nkmk.me/en/python-pip-install-requirements/
  - First: `pip freeze > requirements.txt`
  - Then when installing your program somewhere else: `pip install -r requirements.txt`

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#### Preview: Git (with Git bash), SourceTree, and GitHub (remote repository host)

- Git is a version control system. There are other options too, but Git is probably the most popular.
- Version control systems track the changes you make to files over time, and are absolutely essential to the software development process, especially when working on a team of developers.
- Today we will just be downloading and setting up a couple tools. We will get into specifics in our next lesson

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#### Outline