01_basic-python/06_modules.ipynb

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    "[Table of contents](../toc.ipynb)\n",
    "\n",
    "# Modules\n",
    "\n",
    "* Python comes with a rich standard library of modules, which are organized in packages.\n",
    "* A module is a Python file which you can import in your project.\n",
    "* A package is a collection of modules.\n",
    "* Please take a look at the standard library [https://docs.python.org/3/library/](https://docs.python.org/3/library/)."
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    "* The import of modules is done by `import` keyword.\n",
    "* Next we will import the statistics module from Python's standard lib."
   ]
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   "source": [
    "import statistics"
   ]
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    "## Explicit import\n",
    "\n",
    "* This import was done explicitly. All names of the module are preserved.\n",
    "* You can access the methods with a period `.`."
   ]
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    "statistics.mean([0, 1, 2, 3, 4])"
   ]
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       "1.5"
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    "statistics.median([0, 1, 2, 4])"
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    "## Import with alias\n",
    "\n",
    "* It is often convenient to use a short hand alias."
   ]
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   "source": [
    "import statistics as stat"
   ]
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       "3.3333333333333335"
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    "stat.mean([5, 3, 2])"
   ]
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    "## Import specific module content\n",
    "\n",
    "* You can also import just one function or any other object of a module."
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    "from statistics import mean as my_mean"
   ]
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    "my_mean([1, 2, 3])"
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    "## Implicit import\n",
    "\n",
    "* With an asterisk `*`, you can also import all module content in an implicit way.\n",
    "* However, this could override some older imports or self defined functions! So please use it rarely.\n",
    "* The syntax is `from module import *`."
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    "## Self written modules\n",
    "\n",
    "* If you want to write your own module, you just have to add an empty `__init__.py` in the directory where the module is saved.\n",
    "* So the structure could look like\n",
    "\n",
    "```\n",
    "scritpt.py # a script which imports the module\n",
    "src # a folder\n",
    "  |    __init__.py # empty file\n",
    "  |    my_module.py # your module which contains for instance some functions\n",
    "```"
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    "## Exercise: Modules  (5 minutes)\n",
    "\n",
    "<img src=\"../_static/exercise.png\" alt=\"Exercise\" width=\"75\" align=\"left\">\n",
    "\n",
    "* Write a function, which returns the standard deviation of the list `[1.5, 2.5, 2.5, 2.75, 3.25, 4.75]`\n",
    "\n",
    "**Hint**\n",
    "* You are free to implement the standard deviation from scratch, but is it already out there?"
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   "source": [
    "## Solution\n",
    "\n",
    "Please find one possible solution in [`solution_module.py`](solution_module.py) file."
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    "import sys\n",
    "sys.path.append(\"01_basic-python\")\n",
    "\n",
    "from solution_module import my_std\n",
    "\n",
    "my_std([1.5, 2.5, 2.5, 2.75, 3.25, 4.75])"
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    "## Congrats\n",
    "\n",
    "<img src=\"../_static/flower.jpg\" alt=\"Flower\" width=\"350\" align=\"right\">\n",
    "\n",
    "* These were the basics in Python.\n",
    "* We will move now to Python supporting tools and explore some of the best third party packages, which make Python so powerful."
   ]
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