Splitting one large file into many if the text in a column doesn't match the text in the one before it

Question

I searched for awhile and couldn\'t find a response to this. I have a standard tsv file with the following format:

1    100    101    350    A
1    101    102            


        

Answer 1

Here is a small solution in python using groupby and str.rpartition:

from itertools import groupby

with open("in_file.txt") as f_in:
for name,lines in groupby(f_in.readlines(),key=lambda x:x.rpartition(" ")[2].strip()):
        with open(f"out_{name}.txt","w") as f_out:
            f_out.writelines(lines)