sitc/python/1__10_Modules_Packages.ipynb

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    "![](http://www.upm.es/sfs/Rectorado/Gabinete%20del%20Rector/Logos/UPM/EscPolitecnica/EscUpmPolit_p.gif \"UPM\")"
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   "metadata": {},
   "source": [
    "# Course Notes for Learning Intelligent Systems"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Department of Telematic Engineering Systems, Universidad Politécnica de Madrid, © 2015 Carlos A. Iglesias"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Modules and Packages\n",
    "\n",
    "*Modules* contains definitions and objects that can be reused in other programmes.\n",
    "\n",
    "*Packages* contain subpackages of modules. They are directories and provide the namespace for modules.\n",
    "\n",
    "For example, let's have this package sound, a subpackage effects and the modules echo and surround:\n",
    "\n",
    "<code>\n",
    "babel/\n",
    "    messages/\n",
    "        \\_\\_init\\_\\_.py\n",
    "        plurals.py\n",
    "        catalog.py\n",
    "</code>\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
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   "outputs": [
    {
     "ename": "NameError",
     "evalue": "name 'plurals' is not defined",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mNameError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-9-1ca6b7751408>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m      1\u001b[0m \u001b[1;31m# We can import the module plural with import\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      2\u001b[0m \u001b[1;32mimport\u001b[0m \u001b[0mbabel\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mmessages\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mplurals\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 3\u001b[1;33m \u001b[0mplurals\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mget_plural\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mNameError\u001b[0m: name 'plurals' is not defined"
     ]
    }
   ],
   "source": [
    "# We can import the module plural with import, but we should use the full name\n",
    "import babel.messages.plurals\n",
    "plurals.get_plural()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "(2, '(n != 1)')"
      ]
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     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
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   "source": [
    "import babel.messages.plurals\n",
    "babel.messages.plurals.get_plural()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "(2, '(n != 1)')"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from babel.messages import plurals # with from-import, we can use the short name\n",
    "plurals.get_plural()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(2, '(n != 1)')"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from babel.messages.plurals import get_plural # now we can use directly get_plural()\n",
    "get_plural()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "To write a module, it is just needed to include the code in a file ended with \".py\" and the name of the file is the name of the module.\n",
    "\n",
    "Packages are directories that should have a file \\_\\_.init\\_\\_.py, that can be an empty file or contain initialization code."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Licence"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The notebook is freely licensed under under the [Creative Commons Attribution Share-Alike license](https://creativecommons.org/licenses/by/2.0/).  \n",
    "\n",
    "© 2015 Carlos A. Iglesias, Universidad Politécnica de Madrid."
   ]
  }
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