wradlib.util.import_optional

wradlib.util.import_optional(module)

Allowing for lazy loading of optional wradlib modules or dependencies.

This function removes the need to satisfy all dependencies of wradlib before being able to work with it.

Parameters

module (str) – name of the module

Returns

mod (object) – if module is present, returns the module object, on ImportError returns an instance of OptionalModuleStub which will raise an AttributeError as soon as any attribute is accessed.

Examples

Trying to import a module that exists makes the module available as normal. You can even use an alias. You cannot use the ‘*’ notation, or import only select functions, but you can simulate most of the standard import syntax behavior. >>> m = import_optional(‘math’) >>> m.log10(100) 2.0

Trying to import a module that does not exist, does not produce any errors. Only when some function is used, the code triggers an error >>> m = import_optional(‘nonexistentmodule’) # noqa >>> m.log10(100) #doctest: +ELLIPSIS Traceback (most recent call last): … AttributeError: Module ‘nonexistentmodule’ is not installed. <BLANKLINE> You tried to access function/module/attribute ‘log10’ from module ‘nonexistentmodule’. This module is optional right now in wradlib. You need to separately install this dependency. Please refer to https://docs.wradlib.org/en/stable/installation.html#optional-dependencies for further instructions.