Python – Reload a Module in Python 3.4

pythonpython-3.4python-3.xpython-module

I know this might sound like a really stupid question but whatever. I've made a small script in Python and I've made some changes while in a shell. Normally, on an OS X computer (It's running Python 2.7), I would simply type in reload(the_module) and it would reload my module that includes the changes that I have made. However, when I am reloading the module here (on windows python v. 3.4), it simply gives me this:

>>> reload(instfile)
Traceback (most recent call last):
  File "<pyshell#5>", line 1, in <module>
    reload(instfile)
NameError: name 'reload' is not defined

And then when I type in imp.reload(my_module), it simply says that the function is deprecated. I can't seem to find what the new function (or it's equivalent) would be anywhere so if someone can help me that would be great! 🙂

Best Answer

The imp module was deprecated in Python 3.4 in favor of the importlib module. From the documentation for the imp module:

Deprecated since version 3.4: The imp package is pending deprecation in favor of importlib.

So, you should be using the reload function from there:

>>> import importlib
>>> importlib.reload
<function reload at 0x01BA4030>
>>> importlib.reload(the_module)

Related Solutions

Python – How to import a module given the full path

For Python 3.5+ use:

import importlib.util
spec = importlib.util.spec_from_file_location("module.name", "/path/to/file.py")
foo = importlib.util.module_from_spec(spec)
spec.loader.exec_module(foo)
foo.MyClass()

For Python 3.3 and 3.4 use:

from importlib.machinery import SourceFileLoader

foo = SourceFileLoader("module.name", "/path/to/file.py").load_module()
foo.MyClass()

(Although this has been deprecated in Python 3.4.)

For Python 2 use:

import imp

foo = imp.load_source('module.name', '/path/to/file.py')
foo.MyClass()

There are equivalent convenience functions for compiled Python files and DLLs.

Python – How to execute a program or call a system command

Use the subprocess module in the standard library:

import subprocess
subprocess.run(["ls", "-l"])

The advantage of subprocess.run over os.system is that it is more flexible (you can get the stdout, stderr, the "real" status code, better error handling, etc...).

Even the documentation for os.system recommends using subprocess instead:

The subprocess module provides more powerful facilities for spawning new processes and retrieving their results; using that module is preferable to using this function. See the Replacing Older Functions with the subprocess Module section in the subprocess documentation for some helpful recipes.

On Python 3.4 and earlier, use subprocess.call instead of .run:

subprocess.call(["ls", "-l"])

Best Answer

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Python – How to import a module given the full path

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