Can a Python package name start with a number?

Question

I know that naming a Python module starting with a number is a bad idea, as stated in this other question, but I'm wondering if is it legal to do so in a Python package, not module (aka file).

For example. I want to integrate a Django website with some external APIs and I wanted to create a "third party" package, containing a file for each provider, and I don't know if calling it 3rd_party will become a headache or I should name it third_party instead, to avoid problems.

Note: I don't know if it matters, but I'm using Python 2.7

Martijn Pieters · Accepted Answer · 2013-07-05T11:04:29.620

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No, it cannot. Python package and module names need to be valid identifiers:

identifier ::=  (letter|"_") (letter | digit | "_")*

Identifiers must start with a letter or an underscore.

The import statement defines the grammar for modules as:

module          ::=  (identifier ".")* identifier

Packages are a special kind of module (implemented as a directory with __init__.py file) and are not exempt from these rules.

Technically you can work around this by not using the import statement, as the importlib module and __import__ hook do not enforce the restriction. It is however not a good idea to name your package or module such that you need to use non-standard import mechanisms to make it work.

edited Jul 05 '13 at 11:04

answered Jul 05 '13 at 10:55

Martijn Pieters

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I'm asking about packages, not modules. – Caumons Jul 05 '13 at 10:56
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packages are specialized modules implemented as directories, so the rules still apply. – Martijn Pieters Jul 05 '13 at 10:56
OK, so packages, as well as modules can't start with a number. So, I'll go with `third_party`. Thanks! :) – Caumons Jul 05 '13 at 10:58
I completelly agree with you that using a "hack" is not the way to go! – Caumons Jul 05 '13 at 11:06
it means, I can not have a "-" in my package right? – Sahith Vibudhi Jan 17 '20 at 07:14
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@SahithVibudhi right. A dash is not in the list. Letters, underscores and if it isn’t the first character, digits, only. – Martijn Pieters Jan 17 '20 at 08:20

neuront · Answer 2 · 2013-07-05T11:12:22.407

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Yes.

# 1/x.py dont forget 1/__init__.py
x = 42

Import it from another file

# test.py
p1 = __import__('1.x')
print p1.x.x

edited Jul 05 '13 at 11:12

answered Jul 05 '13 at 11:01

neuront

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In your example `1.py` is a Python module, not a package. – Caumons Jul 05 '13 at 11:02
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Requiring a work-around doesn't make a module that useful by others. – Martijn Pieters Jul 05 '13 at 11:03
I agree with @MartijnPieters, I'll accept his answer as it perfectly explained the case and solved my doubt. Thanks! – Caumons Jul 05 '13 at 11:04
@Caumons Sorry. A similar approach works for a package. I also agree with MartijnPieters. This is just a toy, should not appear in any production. – neuront Jul 05 '13 at 11:14

Can a Python package name start with a number?

2 Answers2