I am trying to learn how to automatically fetch urls from a page. In the following code I am trying to get the title of the webpage:
import urllib.request import re url = "http://www.google.com" regex = r'<title>(,+?)</title>' pattern = re.compile(regex) with urllib.request.urlopen(url) as response: html = response.read() title = re.findall(pattern, html) print(title)
And I get this unexpected error:
Traceback (most recent call last): File "pathtofileCrawler.py", line 11, in <module> title = re.findall(pattern, html) File "C:Python33libre.py", line 201, in findall return _compile(pattern, flags).findall(string) TypeError: can't use a string pattern on a bytes-like object
What am I doing wrong?
You want to convert html (a byte-like object) into a string using
html = response.read().decode('utf-8').
The problem is that your regex is a string, but
html is bytes:
>>> type(html) <class 'bytes'>
Since python doesn’t know how those bytes are encoded, it throws an exception when you try to use a string regex on them.
You can either
decode the bytes to a string:
html = html.decode('ISO-8859-1') # encoding may vary! title = re.findall(pattern, html) # no more error
Or use a bytes regex:
regex = rb'<title>(,+?)</title>' # ^
In this particular context, you can get the encoding from the response headers:
with urllib.request.urlopen(url) as response: encoding = response.info().get_param('charset', 'utf8') html = response.read().decode(encoding)
urlopen documentation for more details.