CODEWITHSUNDEEP
python-3.xdictionary
Rohit
Rohit

Reputation: 39

create nested dictionary from specific elements of 2 list of lists

I have 2 lists in below format .

fa_n=[['DSS', 'DCCS2K01', 'C9790D0E', '5000', 'SPA9'], ['DSS', 'DCCS2K01', 'C9790D0E', '5000', 'SPB13']]
serv_n=[['10:00:56:00:74:79:0d:0e', '50:02:01:34:36:e4:20:gh'], ['10:00:45:00:74:79:0d:0e', '50:02:01:34:36:e4:20:gh']]

I need the following dictionary output wherein the 3rd element of sublist of fa_n will always be the key ,here its '5000' and this in turn should have a key,value pair of 4th element of fa_n and 1st element of serv_n.

Expected output: {key:{key:value}, so on }

{'5000':{'SPA9':'50:02:01:34:36:e4:20:gh'},
{'SPB13','50:02:01:34:36:e4:20:gh'}}

My code 

b_dir=[]
dir_wwn=[]
for arr, fa  in zip(fa_n,serv_n):   
    b_dir.append(f"{arr[3]} ;{arr[4]}")
    dir_wwn.append(f"{arr[4]} ;{fa[1]}")       

print (dict(i.split(';') for i in b_dir)) 
>> {'5000 ': 'SPB13'}

So i thought i would create 2 separate dicts and integrate later to one and moreover i seem to be getting the output just for the last value.

Is there an easier way of going about this?

Upvotes: 0

Views: 399

Answers (1)

a spaghetto
a spaghetto

Reputation: 1142

The trouble you're running into here is that dict() (and dictionary comprehensions as well) will favor the last key-value pair it encounters if it runs into duplicate keys, e.g.:

dict([(1,2), (1,3)]) == {1: 3}

Instead you need to add to the dictionary if it already exists like so:

result = {}

for arr, fa in zip(fa_n, serv_n):   
    key = arr[3]

    if key in result:
        result[key][arr[4]] = fa[1]
    else:
        result[key] = {arr[4]: fa[1]}

print result

which gives you {'5000': {'SPB13': '50:02:01:34:36:e4:20:gh', 'SPA9': '50:02:01:34:36:e4:20:gh'}} as desired.

Upvotes: 1

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