How does init py work

Note that the. It allows you to treat a directory as if it was a python module. Use the interactive interpreter The REPL to import the modules and see if you are getting what you expect. Use Pycharm. Pycharm's fantastic introspection abilities mean that you will immeadiately know whether or not your module is being properly imported as it will indicate an error if not.

It will sometimes also suggest the proper correction. The community edition is free and if you're a student you can get a free subscription to ALL of their products! This is telling Python to look in the current directory for the modules.

I tend not to do that because someone might rename my package top-level package directory. An argument against this is that it can dirty the namespace a bit. It makes the methods available at two locations. I prefer this method because it acts like an API.

Bigger projects and professional packages might definitely go another route. Note that we can still call output and hello directly. Please give your package methods unique names. This is simply how I use it, and the methods described are safe across most common versions of Python. Citizen Upgrade is a community of experts covering technology, society, and personal development.

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Visit us at: www. Bursts of code to power through your day. Note that when using from package import item , the item can be either a submodule or subpackage of the package, or some other name defined in the package, like a function, class or variable. The import statement first tests whether the item is defined in the package; if not, it assumes it is a module and attempts to load it. If it fails to find it, an ImportError exception is raised. Contrarily, when using syntax like import item.

Now what happens when the user writes from sound. Ideally, one would hope that this somehow goes out to the filesystem, finds which submodules are present in the package, and imports them all.

This could take a long time and importing sub-modules might have unwanted side-effects that should only happen when the sub-module is explicitly imported. The only solution is for the package author to provide an explicit index of the package. It is up to the package author to keep this list up-to-date when a new version of the package is released. This would mean that from sound.

It also includes any submodules of the package that were explicitly loaded by previous import statements. Consider this code:. In this example, the echo and surround modules are imported in the current namespace because they are defined in the sound. In fact, this is the recommended notation unless the importing module needs to use submodules with the same name from different packages.

When packages are structured into subpackages as with the sound package in the example , you can use absolute imports to refer to submodules of siblings packages. For example, if the module sound. You can also write relative imports, with the from module import name form of import statement.

These imports use leading dots to indicate the current and parent packages involved in the relative import. From the surround module for example, you might use:. Note that relative imports are based on the name of the current module. This variable can be modified; doing so affects future searches for modules and subpackages contained in the package. While this feature is not often needed, it can be used to extend the set of modules found in a package.

Navigation index modules next previous Python ». Note For efficiency reasons, each module is only imported once per interpreter session. Note On file systems which support symlinks, the directory containing the input script is calculated after the symlink is followed. Some tips for experts: You can use the -O or -OO switches on the Python command to reduce the size of a compiled module. From the surround module for example, you might use: from. Table of Contents 6.

Modules 6. More on Modules 6. Executing modules as scripts 6. The Module Search Path 6. Standard Modules 6. The dir Function 6. Packages 6. Intra-package References 6. Packages in Multiple Directories Previous topic 5. Data Structures Next topic 7.