import urllib.request
req = urllib.request.urlopen('http://search.jd.com/Search?k...')
req
Out[3]:
buf = req.read()
buf = buf.decode('utf-8')
urllist = re.findall(r'//img. .png',buf)
This will normally display the image URL ending in .png
urllist = re.findall(r'//img. .jpg ',buf)
Also basically normal
urllist = re.findall(r'//img. .(png|jpg)',buf)
This can only display the format of a series of pictures, like this ：
'.jpg',
'.jpg',
'.png',
'.jpg',
'.jpg',
'.jpg',
'.jpg',
'.jpg',
'.jpg',
Why is this?
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
Mainly because, when you do not add
(),re.findallwill print out all the matches, but if you add(), it will print the matching, which is()Captured results, so you see a bunch ofjpg/png. Because of this, we need to use()to capture all the matching links so that they can be printed. At the same time, we need to use(?:jpg |png), because what this place needs isto match jpg or png, so we need to use non-capturing grouping syntax.For more about
capture grouping/non-capturing grouping, you can refer to: Link description[png|jpg]
(png|jpg) will be grouped