Python import statement semantics

Question

I\'m having difficulty understanding the import statement and its variations.

Suppose I\'m using the lxml module for scraping websites.

The followin

Answer 1

When you import a package, the interpreter looks up the package on the pythonpath, then if found, parses and runs the package's __init__.py, building a package object from it, and inserts that object in to sys.modules. When importing a module, it does the same thing, except it creates and adds a module object. When you subsequently attempt to access an attribute (aka a member method, class, submodule, or subpackage), it retrieves the corresponding object from sys.modules and attempts a getattr on the module or package object for the child you want. However, if the child is a submodule or subpackage that has not yet been imported, it has not been added to sys.modules or the module or package's attribute list, so you get an AttributeError. Thus, you have to explicitly import a module or package, either in your code, or delegated in a package's __init__.py for it to be available at runtime on its parent.