Built-in Functions

The Python interpreter has a number of built-in functions that are always available. They are listed here in alphabetical order:

__import__( name[, globals [, locals [, fromlist]]] )

This function is invoked by the import statement. It exists so that you can replace it with another function that has a compatible interface, in order to change the semantics of the import statement. For examples of why and how you’d do this, see the standard library modules ihooks and rexec. See also the built-in module imp that defines some useful operations from which you can build your own __import__() function.

For example, the statement import spam results in the call __import_ _('spam', globals(), locals(), []); the statement from spam.ham import eggs results in __import__('spam.ham', globals(), locals(),['eggs']). Even though locals() and ['eggs'] are passed in as arguments, the __import__() function doesn’t set the local variable named eggs; this is done by subsequent code that’s generated for the import statement. (In fact, the standard implementation doesn’t use its locals argument at all, and uses its globals only to determine the package context of the import statement.)

When the name variable is of the form package.module, normally, the top-level package (the name up to the first dot) is returned, not the module named by name. However, when a nonempty fromlist argument is given, the module named by name is returned. This is done for compatibility with the bytecode generated ...

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