Dynamic object creation in Python

Question

I want to abstract away differences between zipfile and rarfile modules. In my code i want to call ZipFile or RarFile constructors depending on file format. Currently i do it like that.

def extract(dir, f, archive_type):
 '''
 archive_type should be 'rar' or 'zip'
 '''
 images = []
 if archive_type == 'zip':
 constructor = zipfile.ZipFile
 else:
 constructor = rarfile.RarFile
 with directory(dir):
 with constructor(encode(f)) as archive:
 archive.extractall()
 os.remove(f)
 images = glob_recursive('*')
 return images

Is there any more elegant way for dynamic object calling?

Answer 1

Classes are first-class objects in Python.

amap = {
 'zip': zipfile.ZipFile,
 'rar': rarfile.RarFile
}
 ...
with amap[archive_type](encode(f)) as archive:
 ...

or

with amap.get(archive_type, rarfile.RarFile)(encode(f)) as archive:
 ...