Jan 20, 2017 · In the Microsoft Windows world, the simplify the way to run a specific Python version, without environment variables setup specifically for each specific version of Python installed, is just by prefixing the python.exe with the path you want to run it from, such as C:\Python25\python.exe mymodule.py or D:\Python27\python.exe mymodule.py

Jun 15, 2017 · In Python all functions must be defined before they can be accessed. This leaves two choices for writing a script: Define the functions at the top: def f1(): # something def f2(): # something # Call f1 f1() # Call f2 f2() Define the functions at the bottom:

The -*-ensures that the line is recognised by GNU Emacs (a text editor popular with some programmers). Note that, contrary to this answer, both the Emacs form and the Vim form are 100% python-docs-recommendation-compatible (as they both match the regexp - "match", by long-standing convention, means "match anywhere in the string", contrary to Python's API).

The Pythonic way to write code is to divide your program into modules that define classes and functions, and a single "main module" that imports all the others and runs. For simple throw-away scripts get used to placing the "executable portion" at the end, or better yet, learn to use an interactive Python shell.

os.environ behaves like a python dictionary, so all the common dictionary operations can be performed. In addition to the get and set operations mentioned in the other answers, we can also simply check if a key exists. The keys and values should be stored as strings. Python 3. For python 3, dictionaries use the in keyword instead of has_key

Jun 24, 2010 · It has been many years since this answer was posted, but I still want to add that if you want to make sure that Python checks the new directory before all of the others when importing, you should put the new directory first in the list, as in sys.path.insert(0, '/path/to/whatever').

However, you asked how to change into whatever directory your Python script is located, even if you don't know what directory that will be when you're writing your script. To do this, you can use the os.path functions: import os abspath = os.path.abspath(__file__) dname = os.path.dirname(abspath) os.chdir(dname)

Here is how it works: the "one canonical place" to store the version number is a .py file, named "_version.py" which is in your Python package, for example in myniftyapp/_version.py. This file is a Python module, but your setup.py doesn't import it! (That would defeat feature 3.)

That can't work because the shell (or other process) is not a child of the Python script in which you are setting the variable. You'll have better luck setting the variables in a shell script. If you then source that script (so that it runs in the current instance of the shell, rather than in a subshell) then they will remain set after the ...

Aug 9, 2020 · Update July 2022: if your TOML file uses setuptools as its build system, setuptools will happily create and install a command-line script. For example, my pyproject.toml file starts like this: [build-system] requires = ["setuptools>=61.0"] build-backend = "setuptools.build_meta"