How can I read large text files in Python, line by line, without loading it into memory?

Question

I need to read a large file, line by line. Lets say that file has more than 5GB and I need to read each line, but obviously I do not want to use readlines() bec

Answer 1

All you need to do is use the file object as an iterator.

for line in open("log.txt"):
    do_something_with(line)

Even better is using context manager in recent Python versions.

with open("log.txt") as fileobject:
    for line in fileobject:
        do_something_with(line)

This will automatically close the file as well.