Pyquery, lxml, BeautifulSoup comparison

parserComparison.py

from bs4 import BeautifulSoup as bs
from pyquery import PyQuery as pq
from lxml.html import fromstring
import re

import requests

import time

def Timer():
	a = time.time()
	while True:
		c = time.time()
		yield time.time()-a
		a = c

timer = Timer()

url = "http://www.python.org/"
html = requests.get(url).text

num = 100000
print '\n==== Total trials: %s =====' %num

next(timer)

soup = bs(html, 'lxml')
for x in range(num):
	paragraphs = soup.findAll('p')
t = next(timer)
print 'bs4 total time: %.1f' %t

d = pq(html)
for x in range(num):
	paragraphs = d('p')
t = next(timer)
print 'pq total time: %.1f' %t


tree = fromstring(html)
for x in range(num):
	paragraphs = tree.cssselect('p')
t = next(timer)
print 'lxml (cssselect) total time: %.1f' %t


tree = fromstring(html)
for x in range(num):
	paragraphs = tree.xpath('.//p')
t = next(timer)
print 'lxml (xpath) total time: %.1f' %t

for x in range(num):
	paragraphs = re.findall('<[p ]>.*?</p>', html)
t = next(timer)
print 'regex total time: %.1f (doesn\'t find all p)\n' %t

Results using Python 3.7

==== Total trials: 100000 =====
bs4 total time: 63.2
pq total time: 8.4
lxml (cssselect) total time: 7.9
lxml (xpath) total time: 5.6
regex total time: 9.6 (doesn't find all p)

Results using python 3.6.5

==== Total trials: 100000 =====
bs4 total time: 325.9 (Not sure why this happened, but it's a record in slowness)
pq total time: 8.9
lxml (cssselect) total time: 7.9
lxml (xpath) total time: 3.5
regex total time: 8.5 (doesn't find all p)

==== Total trials: 100000 =====
bs4 total time: 93.2
pq total time: 7.4
lxml (cssselect) total time: 7.7
lxml (xpath) total time: 5.5
regex total time: 16.4 (doesn't find all p)

In Python 3.7.1:
==== Total trials: 100000 =====
bs4 total time: 69.6
pq total time: 10.1
lxml (cssselect) total time: 9.6
lxml (xpath) total time: 6.3
regex total time: 13.6 (doesn't find all p)

Results using python 3.7.3

==== Total trials: 100000 =====
bs4 total time: 94.1
pq total time: 9.5
lxml (cssselect) total time: 8.6
lxml (xpath) total time: 5.9
regex total time: 12.9 (doesn't find all p)

I tried selectolax and in this case selectolax is 2 times faster than lxml
https://rushter.com/blog/python-fast-html-parser/

from selectolax.parser import HTMLParser

tree = HTMLParser(html)
for x in range(num):
    paragraphs = tree.css('p')
t = next(timer)
print('selectolax total time: %.1f' % t)

==== Total trials: 100000 =====
bs4 total time: 95.4
pq total time: 10.9
lxml (cssselect) total time: 10.0
lxml (xpath) total time: 6.4
regex total time: 14.4 (doesn't find all p)
selectolax total time: 3.4

python 3.9.2

==== Total trials: 100000 =====
bs4 total time: 31.9
pq total time: 4.9
lxml (cssselect) total time: 4.4
lxml (xpath) total time: 3.1
regex total time: 8.5 (doesn't find all p)

Python 3.10.4

==== Total trials: 100000 =====
bs4 total time: 30.1
pq total time: 2.8
lxml (cssselect) total time: 2.6
lxml (xpath) total time: 2.0
regex total time: 6.3 (doesn't find all p)

Python 3.10.1

==== Total trials: 100000 =====
bs4 total time: 45.9
pq total time: 4.6
lxml (cssselect) total time: 4.3
lxml (xpath) total time: 3.3
regex total time: 8.4 (doesn't find all p)

Python 3.11.2

==== Total trials: 100000 =====
bs4 total time: 18.1
pq total time: 2.2
lxml (cssselect) total time: 2.2
lxml (xpath) total time: 1.7
regex total time: 5.2 (doesn't find all p)