Does something like operator.getattr exist to perform a chained attr
lookup?
I came up with the following, but I can not help but think it is
already done and done better.
Peace,
David S.
def compose(funcs):
""" return composite of funcs
this does not support extended call syntax, so each func can
only take a single arg
>>> from operator import add
>>> funcs = [lambda x:add('ANSWER: ', str(x)), lambda x:add(x,100)]
>>> compose(funcs)(9)
'ANSWER: 109'
"""
def _func(arg):
return reduce(lambda v,f: f(v), iter(funcs[::-1]), arg)
return _func
def chained_attrgetter(cattr):
"""
>>> class A: pass
...
>>> a1 = A
>>> a1.a2 = A
>>> a1.a2.a3 = "Hey, now!"
>>> chained_attrgetter("a2.a3")(a1)
'Hey, now!'
"""
return compose([attrgetter(attr) for attr in
cattr.split('.')[::-1]])
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