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@agonzalezro
Created May 30, 2012 23:48
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Do a recursive get over the keys of nested dictionaries
# I always have problems with the names, please help me :)
def rget(dictionary, *args):
'''Recursive `.get()` function.
Do a recursive get over the keys of nested dictionaries.
>>> things = {'a': {'b': {'c': 'd'}}}
>>> rget(things, 'a', 'b', 'c')
'd'
>>> rget(things, 'a', 'b')
{'c': 'd'}
>>> rget(things, 'a')
{'b': {'c': 'd'}}
>>> rget(things, 'a', 'b', 'c', 'd')
>>> rget(things, 'fake_key')
>>> rget(things, 'a', 'fake_key')
'''
to_be_returned = None
if args[1:]:
to_be_returned = rget(dictionary.get(args[0]), *args[1:])
elif args[0:] and isinstance(dictionary, dict):
to_be_returned = dictionary.get(args[0])
return to_be_returned
@grimborg
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def rget(dictionary, *args):
return reduce(lambda d, key: d.get(key), args, dictionary)

@agonzalezro
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Nice! But...

alex turtle:/tmp/2839610 [1012:1]% python -m doctest rget.py
**********************************************************************
File "rget.py", line 16, in rget.rget
Failed example:
    rget(things, 'a', 'b', 'c', 'd')
Exception raised:
    Traceback (most recent call last):
      File "/usr/lib/python2.7/doctest.py", line 1254, in __run
        compileflags, 1) in test.globs
      File "<doctest rget.rget[4]>", line 1, in <module>
        rget(things, 'a', 'b', 'c', 'd')
      File "rget.py", line 20, in rget
        return reduce(lambda d, key: d.get(key), args, dictionary)
      File "rget.py", line 20, in <lambda>
        return reduce(lambda d, key: d.get(key), args, dictionary)
    AttributeError: 'str' object has no attribute 'get'
**********************************************************************
1 items had failures:
   1 of   7 in rget.rget
***Test Failed*** 1 failures.```

@grimborg
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What's "things"?

@agonzalezro
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The doctest example variable?

@grimborg
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If you want it to return None if it can't find the key or if it tries to access a keys of something that's not a dict, I'd just put the reduce in a try block.

@agonzalezro
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FTR because we've already talked about this by chat.

This is exactly what I'm trying to avoid, the need of use try-except blocks or nested ifs.

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