CODEWITHSUNDEEP
pythondictionary
Jack Levent
Jack Levent

Reputation: 75

Grab 2 keys with highest values for nested dictionary

I have a dictionary which looks like this:

bigdict = { 

'a': {'foo':2, 'bar':3, 'baz':7, 'qux':1},
'b': {'foo':6, 'bar':4, 'baz':3, 'qux':0},
'c': {'foo':4, 'bar':5, 'baz':1, 'qux':6}
}

And for each dictionary, I want to be able to grab the 2 keys with the highest values and put the results in a new dictionary.

e.g. 

newbigdict = {
 a: {'baz':7, 'bar':3},
 b: {'foo': 6, 'bar':4},
 c: {'qux':6, 'bar':5}
}

Any ideas? I've been stuck on this for a while. I use Python 3.

Upvotes: 2

Views: 225

Answers (2)

MaxU - stand with Ukraine
MaxU - stand with Ukraine

Reputation: 210912

it can be done pretty easily using pandas module:

In [97]: bigdict = {
   ....: 'a': {'foo':2, 'bar':3, 'baz':7, 'qux':1},
   ....: 'b': {'foo':6, 'bar':4, 'baz':3, 'qux':0},
   ....: 'c': {'foo':4, 'bar':5, 'baz':1, 'qux':6},
   ....: }

In [98]: df = pd.DataFrame.from_dict(bigdict)

In [99]: df
Out[99]:
     a  b  c
bar  3  4  5
baz  7  3  1
foo  2  6  4
qux  1  0  6

In [126]: df.apply(lambda x: x.nlargest(2).to_dict()).to_dict()
Out[126]:
{'a': {'bar': 3, 'baz': 7},
 'b': {'bar': 4, 'foo': 6},
 'c': {'bar': 5, 'qux': 6}}

one-liner:

In [129]: (pd.DataFrame.from_dict(bigdict)
   .....:    .apply(lambda x: x.nlargest(2).to_dict())
   .....:    .to_dict()
   .....: )
Out[129]:
{'a': {'bar': 3, 'baz': 7},
 'b': {'bar': 4, 'foo': 6},
 'c': {'bar': 5, 'qux': 6}}

Upvotes: 0

Bhargav Rao
Bhargav Rao

Reputation: 52151

This can be solved easily using a dictionary comprehension. See this post for more explanation about a Python Dictionary Comprehension 

>>> def findtoptwo(d):
...     toptwo = sorted(d.values())[-2:]
...     return {k:v for k,v in d.items() if v in toptwo}
... 
>>> newdict = {k:findtoptwo(v) for k,v in bigdict.items()}
>>> newdict
{'a': {'bar': 3, 'baz': 7}, 'c': {'qux': 6, 'bar': 5}, 'b': {'foo': 6, 'bar': 4}}

The logic here is simple, For each key-value pair in the dictionary we check if the value is present in the top two values. For this we sort the dictionary values and slice the last two values. Read more about slices in python here and the builtin sorted here.

Upvotes: 1

Related Questions