Reading Files

Opening a file to read

The safest way is to use a with block. It closes the file for you.

python
with open("notes.txt", "r") as f:
    text = f.read()

Reading the whole file

read() returns one big string.

python
with open("notes.txt", "r") as f:
    text = f.read()
    print(text)

Reading line by line

You can loop over the file to get one line at a time.

python
with open("notes.txt", "r") as f:
    for line in f:
        print(line.strip())

strip() removes the newline at the end of each line.

Reading all lines at once

python
with open("notes.txt", "r") as f:
    lines = f.readlines()

File not found errors

If the path is wrong, Python raises FileNotFoundError. Check your folder and spelling.

Common mistakes to avoid

• Forgetting to close the file (use with).
• Printing lines without strip(), which adds extra blank lines.
• Mixing reading and writing in the same open call.

What you should understand after this lesson

• How to open a file safely for reading.
• The difference between read(), readlines(), and looping.
• How to handle missing files.