Append unequal length of values from a list to a dictionary

Scrappy Coco :

I have a dictionary, the keys of which are:

{'A', 'B', 'C', 'D'}

and some examples of list values:

1- [(33.0, 134), (54.0, 113), (21.0, 120)]
2- [(25.0, 153)]
3- [()]

I want to apply the list values to the dictionary keys in order. The expected output will be in case 1-:

{'A' : 33.0,
'B' : 134,
'C' : 54.0,
'D' : 113}

in case 2-:

{'A' : 25.0,
'B' : 153,
'C' : NaN,
'D' : NaN}

in case 3-:

{'A' : NaN,
'B' : NaN,
'C' : NaN,
'D' : NaN}

How can I do this?

CDJB :

As a dictionary comprehension - substitute 'NaN' for np.nan if that's the value you're after.

>>> keys = ['A', 'B', 'C', 'D']

>>> l = [(33.0, 134), (54.0, 113), (21.0, 120)]
>>> dict(zip(keys,([x for sl in l for x in sl]+['NaN']*len(keys))[:len(keys)]))
{'A': 33.0, 'B': 134, 'C': 54.0, 'D': 113}

>>> l = [(25.0, 153)]
>>> dict(zip(keys,([x for sl in l for x in sl]+['NaN']*len(keys))[:len(keys)]))
{'A': 25.0, 'B': 153, 'C': 'NaN', 'D': 'NaN'}

>>> l = [(,)]
>>> dict(zip(keys,([x for sl in l for x in sl]+['NaN']*len(keys))[:len(keys)]))
{'A': 'NaN', 'B': 'NaN', 'C': 'NaN', 'D': 'NaN'}

Explanation:

We use zip() to zip the keys list of size n with the flattened list of tuples, appending a list of n 'NaN' values to the end, and then chopping off the first n values. The dict() constructor accepts a zipped list as an argument.