I would like to know how to convert a string input into a variable name to use into Python code. A concrete example:
def insrospect(foo, bar):
requested_module = makestringvariable(foo)
requested_object = makestringvariable(bar)
import requested_module
for item in inspect.getmemebers(requested_module.requested_object):
member = makestringvariable(item[0])
if callable(requested_object.member):
print item
if __name__ == '__main__':
introspect(somemodule, someobject)
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So here above, because i do not know which module to introspect before launching, i need to convert the string to a usable module name and because getmembers()
returns the members as strings, i also need them to be converted into usable variable names to check if they are callable.
Is there such a makestringvariable()
function?
with the __import__ function and the getattr magic, you will be able to directly write this :
import importlib
def introspect(foo, bar):
imported_module = importlib.import_module(foo)
imported_object = getattr(imported_module, bar)
for item in inspect.getmembers(imported_object):
if callable(getattr(imported_object, item[0]):
print item
if __name__ == '__main__':
introspect(somemodule, someobject)
You can't convert a string into a variable as such, because variables are part of your code, not of your data. Usually, if you have a need for "variable variables", as it were, you would use a dict:
data = {
foo: foo_value,
bar: bar_value
}
And then use data[foo]
instead of trying to use foo
as a variable. However, in this example you're actually asking about importing a module through a string, and about getting attributes using a string name, both of which are services Python provides: through the __import__
and getattr
functions.
Members of a module are just attributes on that module, so you can use getattr
on the module object to retrieve them.
The module objects themselves are stored in the sys.modules
dictionary:
module = sys.modules[modulename]
member = getattr(module, membername)
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