python - Converting python dictionary values to respective key-value pairs

Question

Currently I am working with Django querysets and am getting a result like this:

[{'week': 29, 'avg': 137.6}, {'week': 30, 'avg': 138.6}, {'week': 31, 'avg': 138.06666666666666}]

As you can see, its a list of dictionaries.

I want to deal with simply:

{29: 137.6, 30: 138.6, 31: 138.066}

I'm having some trouble looping my head through all this. Any help would be appreciated. Thank you.

Answer 1

Simply use dictionary comprehension :

{ d['week'] : d['avg'] for d in data }

Where data is your list of dictionaries. This produces:

>>> { d['week'] : d['avg'] for d in data }
{29: 137.6, 30: 138.6, 31: 138.06666666666666}

The dictionary comprehension will thus iterate through data , and for every element d (a dictionary), it will associate d['week'] (key) with d['avg'] (value) in the result.

In case it is not a list of dictionaries, but still a queryset, you should - like @JonClemens says - use the following expression:

dict(queryset.values_list('week','avg'))

Here values_list('week','avg') will construct an iterable of 2-tuples that contain the week as first element, and the average as second element. If the dict(..) constructor obtains an iterable of 2-tuples, it will construct a dictionary where the first element of every tuple is the key, and the second element of the tuple the associated value.