Paths and text files

A path points to a file or directory. pathlib.Path joins path parts in a way that works across operating systems. A relative path such as notes.txt is relative to the current working directory when you run the program.

For file practice, download the Python practice files v1.0.0 bundle. The examples write their own files, so the samples stay unchanged. Work on a copy if you edit a sample.

from pathlib import Path

notes = Path("my_notes.txt")
notes.write_text("Practice Python today.\n", encoding="utf-8")
print(notes.read_text(encoding="utf-8").strip())

Practice Python today.

Appending without replacing

write_text() replaces an existing file. To add text to the end instead, open the file in append mode with a with block. The with block closes the file afterward.

from pathlib import Path

notes = Path("my_notes.txt")
notes.write_text("First note\n", encoding="utf-8")
with notes.open("a", encoding="utf-8") as file:
    file.write("Second note\n")
print(notes.read_text(encoding="utf-8").splitlines())

['First note', 'Second note']

Why this works

Path("my_notes.txt") uses the process’s current working directory, which is usually the folder you entered in the terminal before running Python. It is not automatically the folder where the .py file lives. write_text() replaces file contents; opening with "a" appends to existing contents.

Practice

Create a practice text file with two lines. Read it back using UTF-8 and print the lines. Check the file in your project folder. Then read the sample notes.txt from the practice bundle with read_text(encoding="utf-8") and print its lines.

Try another case

If my_notes.txt contains "old" and write_text("new") runs, what remains in the file?