How do i read file in python with fixed start and end

Question

I'm trying to read a file which is of 3GB and compressed in json.gz . I found one thing that its content between lines 1 to 10 cannot be read by 12GB of RAM as

for f in s_file:
    print(f)

try to read from memory. And I'm trying it on GooleColab.

This is code, I have successfully read

size_to_read = 1024000
def gunzip_shutil(source_filepath, dest_filepath,):
    with gzip.open(source_filepath, 'rb') as s_file:
      print(s_file.read(size_to_read).decode())

gunzip_shutil(f"{default_path_download}/{name}", "")

What I want is that read from 0 to 8192 then it starts reading from 8192 so that I can see bytes by bytes as it won't overload memory.

Something like :

print(f.read(range(4096, 8192)))

Thanks For Your Help!

Answer 1

You can try something like this:

test.py:

N = 8192


def main():
    buf = bytearray(N)

    with open("10G.bin", "rb") as f:
        while f.readinto(buf):
            mview = memoryview(buf)
            print(mview[32:40].tobytes())

            break # tmp


if __name__ == "__main__":
    main()

The memoryview object just references a particular slice without copying bytes.