How to read a file line by line in Python

March 16, 2026 · 1 min read · Updated March 16, 2026 · beginner

python files io

The most common way to read a file line by line is using a for loop directly on the file object:

with open("example.txt") as f:
    for line in f:
        print(line)

This is the Pythonic approach and works efficiently for large files because it iterates lazily — only one line is in memory at a time.

If you need a list of all lines upfront:

with open("example.txt") as f:
    lines = f.readlines()

for line in lines:
    print(line)

Be careful with this approach for large files — it loads everything into memory at once.

For more control over the iteration:

with open("example.txt") as f:
    for line in iter(f.readline, ""):
        process(line)

This stops when readline() returns an empty string (end of file).

Each line includes the trailing newline character. Remove it with strip():

with open("example.txt") as f:
    for line in f:
        print(line.strip())

See Also