20210913/3_1___CSS.ipynb

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   "source": [
    "# Course on webscraping\n",
    "\n",
    "*By Olav ten Bosch, Darius Keijdener, Dick Windmeijer*"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
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   "source": [
    "# Imports:\n",
    "import requests                  # for issueing HTTP requests\n",
    "from bs4 import BeautifulSoup    # for parsing and navigating HTML results\n",
    "import time                      # for sleeping between multiple requests\n",
    "headers = {'user-agent': 'scrapingCourseBot'}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Documentation:\n",
    "- [Requests.py](http://docs.python-requests.org)\n",
    "- [Beautifulsoup.py](https://www.crummy.com/software/BeautifulSoup/bs4/doc/)\n",
    "- [CSS selectors](https://www.w3schools.com/cssref/css_selectors.asp)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Soup with CSS selectors: (select):"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Get page in soup:\n",
    "r5 = requests.get('https://www.cbs.nl/en-gb', headers=headers)\n",
    "print(r5.url, r5.status_code)\n",
    "soup = BeautifulSoup(r5.text, 'lxml')"
   ]
  },
  {
   "cell_type": "code",
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   "source": [
    "# Find all elements with a tag:\n",
    "\n",
    "# find_all:\n",
    "#print(soup.find_all(\"h2\"))\n",
    "#print(\"\")\n",
    "#print(soup.find_all(\"h3\"))\n",
    "\n",
    "#CSS:\n",
    "print(soup.select(\"h2\"))\n",
    "print(\"\")\n",
    "print(soup.select(\"h3\"))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Find all elements belonging to a class:\n",
    "\n",
    "# find_all:\n",
    "#print(soup.find_all(\"a\", class_=\"thumbnail\"))\n",
    "\n",
    "# CSS:\n",
    "print(soup.select(\"a.thumbnail\"))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# find all elements with an id:\n",
    "\n",
    "# find_all:\n",
    "#print(soup.find_all(\"section\", id=\"aside-main\"))\n",
    "\n",
    "# CSS:\n",
    "print(soup.select(\"section#aside-main\"))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# The power of CSS is in traversing the tree in one statement:\n",
    "# Get all headlines via a CSS selector:\n",
    "headlines = soup.select(\"a.thumbnail h3\")\n",
    "for headline in headlines:\n",
    "    print(headline.text)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Get all links of thumbnails via CSS:\n",
    "thumbnails = soup.select(\"a.thumbnail\")\n",
    "for thumbnail in thumbnails:\n",
    "    print(thumbnail['href'])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Get all h3s in the aside section:\n",
    "aside_H3s = soup.select(\"section#aside-main h3\")\n",
    "for a in aside_H3s:\n",
    "    print(a.text)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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