Hi,
Background: In my code I use sqlalchemy to read SQL server data. I want to
write that data to HDF5 using pytables (see 'declaring a column descriptor':
https://www.pytables.org/usersguide/tutorials.html). My question is not about
pytables or sqlalchemy per se, but I thought it would be informative to mention
this.
What is the best way to dynamically set class variables? I am looking for a
generalization of something like this:
class Parent: pass
class Child(Parent):
col1 = 'str'
col2 = 'int'
Several (im)possible solutions:
# -------
class Parent: pass
class_vars = dict(col1='str', col2='int')
# approach 1
Child = type('Child', (Parent,), class_vars)
# approach 2
class Child(Parent): pass
Child.__dict__.update( class_vars ) # AttributeError: 'mappingproxy' object
has no attribute 'update'
# approach 3
class Child(Parent): pass
for k, v in class_vars.items():
setattr(Child, k, v)
I initially chose approach #1, but I find this way of defining a class quite
cryptic (but then, it's part of the language definition!). What's the best way
to do this? I am using Python 3.5 (Windows). Thanks in advance!
Best wishes,
Albert-Jan
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