Stripping a block of text from a file using python

Question

I have to basically strip out a block of text from file1. The file1 is huge of many thousand lines (~3GB size). The block looks as below,

line 1
line 2


        

Answer 1

Your proposal is simple to understand and implement. This also makes it easy to debug, maintain, and update. Yes, this is a good approach to use.

start_pattern_list =   # Make this a list of all the patterns from file2
stop_pattern = "}\n"
out_flag == False
for line in <input file>:
    if '<' in line:
        if any(p in line for p in start_pattern_list):
            out_flag = True     # Turn on output
    if out_flag:
        out_file.write(line)
    if stop_pattern in line:
        out_flag = False    # Turn off output

This works for simple files: no nested braces, the input trigger (pattern) appears only as a pattern (not embedded within the braces).