To help evaluate the trade-offs between the three scraping approaches described in the section, Three approaches to scrape a web page, it would be helpful to compare their relative efficiency. Typically, a scraper would extract multiple fields from a web page. So, for a more realistic comparison, we will implement extended versions of each scraper which extract all the available data from a country's web page. To get started, we need to return to our browser to check the format of the other country features, as shown here:

By using our browser's inspect capabilities, we can see each table row has an ID starting with places_ and ending with __row. The country data is contained within these rows in the same format as the area example. Here are implementations that use this information to extract all of the available country data:

FIELDS = ('area', 'population', 'iso', 'country', 'capital', 'continent', 'tld', 'currency_code', 'currency_name', 'phone', 'postal_code_format', 'postal_code_regex', 'languages', 'neighbours') 

import re 
def re_scraper(html): 
    results = {} 
    for field in FIELDS: 
        results[field] = re.search('<tr id="places_%s__row">.*?<td class="w2p_fw">(.*?)</td>' % field, html).groups()[0] 
    return results 

from bs4 import BeautifulSoup 
def bs_scraper(html): 
    soup = BeautifulSoup(html, 'html.parser') 
    results = {} 
    for field in FIELDS: 
        results[field] = soup.find('table').find('tr',id='places_%s__row' % field).find('td',                  class_='w2p_fw').text 
    return results 

from lxml.html import fromstring
def lxml_scraper(html): 
    tree = fromstring(html) 
    results = {} 
    for field in FIELDS: 
        results[field] = tree.cssselect('table > tr#places_%s__row > td.w2p_fw' % field)[0].text_content() 
    return results 

def lxml_xpath_scraper(html):
    tree = fromstring(html)
    results = {}
    for field in FIELDS:
        results[field] = tree.xpath('//tr[@id="places_%s__row"]/td[@class="w2p_fw"]' % field)[0].text_content()
    return results