Python - Print line based on partial string

Question

I have 2 files that I am wanting to check against each other and pull out the line that they are contained in.

I was trying to do it with regex but I keep getting this error, presuming it's because I'm reaching into a file rather than just presenting a string directly

File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.9_3.9.2544.0_x64__qbz5n2kfra8p0\lib\re.py", line 248, in finditer
    return _compile(pattern, flags).finditer(string)
TypeError: expected string or bytes-like object

This is what I'm using for the regex search

regex = r"\d(.*(10.0.0.0).*)"

with open('test1.txt', 'r') as file1:
    test = file1.read().splitlines()
    matches = re.finditer(regex, test)

    for matchNum, match in enumerate(matches, start=1):
        print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group()))

I have also tried this, but still comes up with an error

with open("test1.txt") as file1, open("test2") as file2:
    st = set(map(str.rstrip,file1))
    for line in file2:
        spl = line.split(None, 1)[0]
        if spl in st:
            print(line.rstrip())

The error is

IndexError: list index out of range

I am trying to match a list of IPs to the output from a router, so the test2 file will look like this

10.0.0.0/8
11.0.0.0/8
12.0.0.0/8
13.0.0.0/8

With the router output looking like

1 X test         10.0.0.0/8                          nov/19/2021 13:03:08
2 X test         11.0.0.0/8                          nov/19/2021 13:03:08
3 X test         12.0.0.0/8                          nov/19/2021 13:03:08
4 X test         13.0.0.0/8                          nov/19/2021 13:03:08

I am wanting the entire line from the router to be matched just with the IP rather than having to put the entire expected output

Hope this is enough to go off, still pretty new to all this, cheers

Answer 1

Full answer is

with open("router_output.txt") as file1, open("list_of_ips.txt") as file2:
    ips_to_keep = file2.read().splitlines()
    router_lines = file1.read().splitlines()

ips_to_keep = [" " + ip + " " for ip in ips_to_keep]

for line in router_lines:
    if any(ip in line for ip in ips_to_keep):
        print(line)

assuming that your file has spaces and not tabs :)