Question

How do I reimport a module? I want to reimport a module after making changes to its .py file.

Answer 1

For Python 3.4+:

import importlib
importlib.reload(nameOfModule)

For Python < 3.4:

reload(my.module)

From the Python docs

Reload a previously imported module. The argument must be a module object, so it must have been successfully imported before. This is useful if you have edited the module source file using an external editor and want to try out the new version without leaving the Python interpreter.

Don’t forget the caveats of using this method:

• When a module is reloaded, its dictionary (containing the module’s global variables) is retained. Redefinitions of names will override the old definitions, so this is generally not a problem, but if the new version of a module does not define a name that was defined by the old version, the old definition is not removed.

• If a module imports objects from another module using from ... import ..., calling reload() for the other module does not redefine the objects imported from it — one way around this is to re-execute the from statement, another is to use import and qualified names (module.*name*) instead.

• If a module instantiates instances of a class, reloading the module that defines the class does not affect the method definitions of the instances — they continue to use the old class definition. The same is true for derived classes.