How to add property to a class dynamically?

Question

The goal is to create a mock class which behaves like a db resultset.

So for example, if a database query returns, using a dict expression, {\'ab\':100, \'cd\'

Answer 1

To answer the main thrust of your question, you want a read-only attribute from a dict as an immutable datasource:

The goal is to create a mock class which behaves like a db resultset.

So for example, if a database query returns, using a dict expression, {'ab':100, 'cd':200}, then I would to see

>>> dummy.ab
100

I'll demonstrate how to use a namedtuple from the collections module to accomplish just this:

import collections

data = {'ab':100, 'cd':200}

def maketuple(d):
    '''given a dict, return a namedtuple'''
    Tup = collections.namedtuple('TupName', d.keys()) # iterkeys in Python2
    return Tup(**d)

dummy = maketuple(data)
dummy.ab

returns 100