how to reload a Class in python shell?
If I import a module defining a class of the same name belonging to a package, it is imported as a Class, not a Module because of the __init__.py of the parent package. See different import results at different directories for details. In Python shell or ipython shell, if I do
from MyPak import MyMod
MyModule is always imported as Class thus I can not reload it (reload() works only for modules). Run
from MyPak import MyMod
again does not seem to update the Class definition. Could anyone suggest a way to update the class in python shell?
ps. without restarting the python interpreter.
pps. Just in case you have the code in hand and want to test it: I am actually talking about BioPython, and I am working on Bio.PDB.PDBParser. I have an ipython shell (v0.10) and edit PDBParser.py. Just got no way to reload it in ipython.
so here is what I did:
# start ipython v0.10
import Bio
from Bio.PDB import PDBParser
p = PDBParser()
s = p.get_structure()
# then I make changes,e.g. simply print some text, in PDBParser.py
del Bio
del PDBParser
del s
import Bio # or reload(Bio) without deleting all the objects
from Bio.PDB import PDBParser
p = PDBParser()
s = p.get_structure() # expected output after change not seen :(
I could not see the printed text. The changes were not applied somehow.
Answer
On Python 3 only, import the reload function:
>>> from importlib import reload
On both Python 2.x, and 3.x, you can then simply call reload on the module:
>>> import MyPak
>>> reload(MyPak)
>>> from MyPak import MyMod
However, instances of the old class will not be updated (there's simply no code that describes the update mechanism).