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    "#users.py\n",
    "#Investigando usuários\n",
    "# https://classroom.udacity.com/nanodegrees/nd002/parts/0021345404/modules/316820862075462/lessons/768058569/concepts/8426285720923#\n",
    "#!/usr/bin/env python\n",
    "# -*- coding: utf-8 -*-\n",
    "import xml.etree.cElementTree as ET\n",
    "import pprint\n",
    "import re\n",
    "\"\"\"\n",
    "Your task is to explore the data a bit more.\n",
    "The first task is a fun one - find out how many unique users\n",
    "have contributed to the map in this particular area!\n",
    "\n",
    "The function process_map should return a set of unique user IDs (\"uid\")\n",
    "\"\"\"\n",
    "\n",
    "osm_file = open(\"/media/vagner/Seagate Expansion Drive/500Gb/\"+\n",
    "                \"DiskExternoVagner/Cursos/CientistaDados/\"+\n",
    "                \"Modulo_4/DW-OSM-RMSP/sample.osm\", \"r\")\n",
    "\n",
    "\n",
    "def get_user(element):\n",
    "    # see if the key exists:\n",
    "    if element.get('uid'):\n",
    "        uid = element.attrib[\"uid\"]\n",
    "        return uid\n",
    "    else:\n",
    "        # you want this function to return None if the key doesn't exist\n",
    "        return None\n",
    "\n",
    "\n",
    "def process_map():\n",
    "    users = set()\n",
    "    for _, element in ET.iterparse(osm_file):\n",
    "        if get_user(element):\n",
    "            users.add(element.attrib[\"uid\"])\n",
    "    return users\n",
    "\n",
    "def test():\n",
    "\n",
    "    users = process_map()\n",
    "    print len(users)\n",
    "    print(users)\n",
    "    \n",
    "if __name__ == \"__main__\":\n",
    "    test()\n",
    "    osm_file.close()"
   ]
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