Python Intro 01.ipynb

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    "# Acquiring Python\n",
    "\n",
    "* Assumption: you're on Windows or Linux (if on Mac, give homebrew a try, but I don't have one at my disposal)\n",
    "\n",
    "## Installing prerequisites on Windows\n",
    "\n",
    "* in the start menu search enter `cmd`\n",
    "    * **NB:** this can be done unelevated!\n",
    "* `winget install -e --id Python.Python.3.13`\n",
    "* `winget install -e --id astral-sh.uv`\n",
    "* `uv tool install notebook`\n",
    "    * `setx PATH \"%USERPROFILE%\\.local\\bin;%PATH%\"` (required to be able to invoke `jupyter-notebook`)\n",
    "\n",
    "### Optionally\n",
    "\n",
    "For a decent editor on Windows install Notepad++ or stick with your favorite, if you got one already:\n",
    "\n",
    "* `winget install -e --id Notepad++.Notepad++`\n",
    "\n",
    "## Installing prerequisites on Debian-based Linux (Debian, Ubuntu, Mint ...)\n",
    "\n",
    "* `sudo apt update`\n",
    "* `sudo apt install python3 jupyter-notebook`\n",
    "\n",
    "### Optionally\n",
    "\n",
    "To make `python3` available as `python` install `python-is-python3`. This is especially useful when dealing with a system that has both Python 2.x and Python 3.x installed.\n",
    "\n",
    "* `sudo apt install python-is-python3`\n",
    "\n",
    "## Optionally: download the docs for offline perusal\n",
    "\n",
    "* Head to https://docs.python.org/3/download.html in your favorite browser\n",
    "* Download your choice of the documentation\n",
    "    * Hint: the HTML version -- once unpacked -- is pretty much the same as [the docs.python.org website](https://docs.python.org/3/), except it works locally (including the search!)"
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    "# First steps\n",
    "\n",
    "## On Windows\n",
    "\n",
    "* hit `Win+r` (Windows key and R simultaneously), then enter `py` and hit Return/Enter\n",
    "* you will be met by the so-called REPL (Read-Eval-Print Loop) prompt, e.g.:\n",
    "\n",
    "```\n",
    "Python 3.12.8 (tags/v3.12.8:2dc476b, Dec  3 2024, 19:30:04) [MSC v.1942 64 bit (AMD64)] on win32\n",
    "Type \"help\", \"copyright\", \"credits\" or \"license\" for more information.\n",
    ">>>\n",
    "```\n",
    "\n",
    "## On Linux\n",
    "\n",
    "* in a terminal start `python3`\n",
    "* you will be met by the so-called REPL (Read-Eval-Print Loop) prompt, e.g.:\n",
    "\n",
    "```\n",
    "$ python\n",
    "Python 3.12.7 (main, Oct  1 2024, 11:15:50) [GCC 14.2.1 20240910] on linux\n",
    "Type \"help\", \"copyright\", \"credits\" or \"license\" for more information.\n",
    ">>>\n",
    "```\n",
    "\n",
    "## Common part\n",
    "\n",
    "* Enter `quit()` and hit Return/Enter to leave, or\n",
    "    * on Windows: hit `Ctrl+z`\n",
    "    * on Linux: hit `Ctrl+d`"
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    "# Exercises for later, for inclined participants\n",
    "\n",
    "## Common part\n",
    "\n",
    "If you start to write Python scripts, you should ideally use something like the following as the first two lines:\n",
    "\n",
    "```\n",
    "#!/usr/bin/env python3\n",
    "# -*- coding: utf-8 -*-\n",
    "```\n",
    "\n",
    "The first line is relevant on Unix (incl. Linux) as it tells the system what interpreter to use. The second one is a hint to the Python interpreter itself that the file is encoded as UTF-8. If you use any non-English characters or non-Latin alphabets or want to sprinkle your scripts with emojis this is the encoding you will need. UTF-8 is a default, so for the most part you don't need to know more. When in doubt, approach one of the more tech-savvy folks and ask.\n",
    "\n",
    "## On Windows\n",
    "\n",
    "* On Windows prefer to use the Python Launcher `py.exe` which comes installed by default in recent Python versions\n",
    "    * Example: `py -3 .\\myscript.py`\n",
    "\n",
    "If you have a Python script `foobar.py`, you could also place a `foobar.cmd` next to that and populate the `.cmd` with the following content:\n",
    "\n",
    "```\n",
    "py -3 \"%~dpn0.py\" %*\n",
    "```\n",
    "\n",
    "This will allow you to double click the script or conveniently start it from a console window. Throw in a `@pause` as second line to have the console window remain once the Python script finishes.\n",
    "\n",
    "This little wrapper script will simply invoke a script by its own name with `.cmd` replaced by `.py` and passing all command line arguments.\n",
    "\n",
    "## On Linux\n",
    "\n",
    "* On Linux you need to make sure to set the x bit in the file mode. So with a `foobar.py` you'd run `chmod +x foobar.py` to make it executable\n",
    "    * This _requires_ the first line starting with `#!` from the common part above! This line is variously called \"shebang\" and \"hashbang\" owed to the fact that `#` is often called the hash sign and `!` is colloquially called bang, e.g. in American English."
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