os-filenotfounderror-wrong-relative-path

FileNotFoundError: wrong relative path

Occurs when the file exists, but Python can't find it from the current working directory.

reproduce.py

with open("data.txt", "r") as f:
    content = f.read()

print(content)

Error message

FileNotFoundError: [Errno 2] No such file or directory: 'data.txt'

Fix

import os

base_dir = os.path.dirname(__file__)
file_path = os.path.join(base_dir, "data.txt")

with open(file_path, "r") as f:
    content = f.read()

print(content)

Reflection

Thought the file was in the same folder, but Python was running from a different location.