[SOLVED] python deleting a certain number of lines from a file given a keyword

bindo · 04-26-2017, 08:28 AM

Newbie here and I'd really appreciate your help in order for me to determine whats the best way to go with below scenario. Please note I'm using python 2.7.X

I've got a file "file.txt" in a centos 7 box which has following lines in it. (Pay attention to the new lines)

Code:

blah blah blah

ID:name1:1bj409ju9
how are you

Im good 100
blah blah

ID:name2:987krjtu
not so good

too bad 900
blah blah

some words blah blah

As you notice the lines start with "ID" have a pattern. My attempt is to search for ID:name[x] and delete 5 lines (including the space). for an instance say i want to delete below set of lines from the file.

Code:

ID:name1:10.1.1.10
how are you

I'm good 100
blah blah

I tried the following code but it deletes only the lines matching "somename1". Please advice.

Code:

#!/usr/bin/python
import fileinput

filename = r"file.txt"
counter = -1
for linenum,line in enumerate(fileinput.FileInput(filename, inplace=1)):
    if "name1" in line:
        counter = linenum + 6
        if linenum == counter:
            line.strip()
    else:
        print line,

Please note that I want to get rid of the new empty line in between "blah blah" and "ID:name2:987krjtu". Please help.

ondoho · 04-26-2017, 12:04 PM

does it have to be python? to me it sounds like a perfect use case for sed.
https://duckduckgo.com/?q=sed+delete...lowing+pattern

pan64 · 04-26-2017, 12:08 PM

if you want to do it with python take care about your counter and linenum.
I mean you need to read all the lines, but you need to skip some of them, but the implemented logic does not really take care about skipping...

bindo · 04-28-2017, 08:09 PM

@ondoho,

Thanks so much. Eventhough I prefer to do it within python what you've suggested works a huge deal too.