Python. How To Print A Certain Part Of A Line After It Had Been "re.searched" From A File

Could you tell me how to print this part of the line only '\w+.226.\w.+' ? Code VSP = input('Номер ВСП (четыре цифры): ') a = re.compile(r'\w+.226.\w.+'+VSP) b=

Solution 1:

You will need to modify your regex slightly to separate the trailing characters in the IP and the spaces that separate it from VSP. Adding a capture group will let you select the portion with just the IP address. The updated regex looks like this:

'(\d+\.226\.\S+)\s+' + VSP

\S (uppercase S) matches any non-whitespace, while \s (lowercase s) matches all whitespace. I replaced the first \w with the more specific \d (digits), and . (any character at all) with \. (actual period). The second \w is now \S, but you could use \d+\.\d+ if you wanted to be more specific.

Using the first capture group will give you the IP address:

print(b.group(1))

If you are looking for a single IP address once, not compiling your regex is fine. Also, reading in a small file in its entirety is OK as long as the file is small. If either is not the case, I would recommend compiling the regex and going through the file line by line. That will allow you to discard most lines much faster than using a regex would do.

Solution 2:

I see you already have an answer.You can also try this regex if you were to separate the two groups by the whitespace:

import re

a = re.compile(r'(.+?)\s+(.+)') # edit: added ? to avoid# greedy behaviour of first .+# otherwise multiple spaces after the# address will be caught into# b.group(1), as per @Mad comment

b=re.search(a, '10.226.27.60    1020')
print (b.group(0))
print (b.group(1))
print (b.group(2))

or customize the first group regexp to your needs.

Edit: This was not meant to be a proper answer but more of a comment wich I didn't think was readable as such; I am trying only to show group separation using regex, wich seems OP didn't know about or didn't use. That is why I am not matching .226. because OP can do that. I also removed the file read part, which isn't needed for demonstration. Please read @Mad answer because its quite complete and in fact also shows how to use groups.