Why are underscores better than hyphens for file names?

python naming
atp picture atp · Apr 29, 2010 · Viewed 20k times · Source

From Building Skills in Python:

A file name like exercise_1.py is better than the name execise-1.py. We can run both programs equally well from the command line, but the name with the hyphen limits our ability to write larger and more sophisticated programs.

Why is this?

Answer

Daniel G picture Daniel G · Apr 29, 2010

The issue here is that importing files with the hyphen-minus (the default keyboard key -; U+002D) in their name doesn't work since it represents minus signs in Python. So, if you had your own module you wanted to import, it shouldn't have a hyphen in its name:

>>> import test-1
  File "<stdin>", line 1
    import test-1
               ^
SyntaxError: invalid syntax
>>> import test_1
>>>

Larger programs tend to be logically separated into many different modules, hence the quote

the name with the hyphen limits our ability to write larger and more sophisticated programs.

Related questions

Is it ok to use dashes in Python files when trying to import them?

Basically when I have a python file like: python-code.py and use: import (python-code) the interpreter gives me syntax error. Any ideas on how to fix it? Are dashes illegal in python file names?

Read More
Python "private" function coding convention

When writing a python module and functions in it, I have some "public" functions that are supposed to be exposed to outsiders, but some other "private" functions that are only supposed to be seen and used locally and internally. I …

Read More
Folder naming convention for python projects

What is the naming convention in python community to set names for project folders and subfolders? my-great-python-project my_great_python_project myGreatPythonProject MyGreatPythonProject I find mixed up in the github. Appreciate your expert opinion.

Read More