Python - Parsing multiple lines of text from file -

i stuck on problem working on.

it involves opening file reading line , comparing next 2 lines in file it. move down 1 line, ie second line in file , compare next 2 lines again.

i having hard time creating loop go through these steps.

so far have done

write_file = input_file[:-3] + "bak" read_file = input_file  open(write_file, "w") write:     open(read_file,"r") read:         line in read:             line1 = line 

thank you.

something like:

tri_lines = [lines[i:i+3] in range(0,len(lines),3)]  #then can iterate through:  triplet in tri_lines:      # code here, compare tri_lines[0] tri_lines[1] etc. 

i'll leave task of getting lines of file list.

note you'll need simple validation handle cases file not have number of lines divisible 3.

you can

for triplet in [lines[i:i+3] in range(0,len(lines),3)]:     if triplet[0] == triplet[1]:         #do     if triplet[0] == triplet[2]:         #do 

though might not clear