CODEWITHSUNDEEP
pythonpython-2.7
Snowman08
Snowman08

Reputation: 425

Issues with a 3 list combination into one dictonary

Question is how would I combine three list's together while iterating through them.

To explain it:

list_a has a bunch of the same keys
list_b has values
list_c has values
*Do the list have to be in order and what if they aren't????

Here are my list:

#list_a would be the key  

list_a = ['MACHINE TOOLS', 'MACHINE TOOLS', 'FLUID', 'MACHINE TOOLS','MACHINE TOOLS', 'VALVES', 'FLUID', 'VALVES']

list_b = ['GROUP A MTOOLS', 'GROUP B MTOOLS', 'GROUP C MTOOLS', 'GROUP D MTOOLS', 'GROUP A FLUID', 'GROUP B FLUID', 'GROUP A VALVES', 'GROUP B VALVES'] 

list_c = ['1', '2', '3', '44', '46', '47', '52', '53']

here is what I would like to see come out of this

{
    'MACHINE TOOLS': { 'GROUP A MTOOLS': '1', 'GROUP B MTOOLS': '2', 'GROUP C MTOOLS': '3', 'GROUP D MTOOLS': '44'}, 

    'FLUID': {'GROUP A FLUID': '46', 'GROUP B FLUID': '47'},

    'VALVES': {'GROUP A VALVES': '52', 'GROUP B VALVES': '53'}

}

What I've tried:

dic={ list_as:{ list_bs:[list_c] for list_bs in list_bs} for list_as in list_a}

^This comes out close to what I want but for some reason list_c's values aren't being iterated-- I've tried a for loop with them and still no luck.

Upvotes: 0

Views: 58

Answers (1)

user3030010
user3030010

Reputation: 1857

Okay, since the keys in the first dictionary don't line up with the keys in the second, it looks like you're first going to have to define a static mapping between some of these names. That would look something like:

name_mapping = {"MTOOLS": "MACHINE TOOLS",
                "FLUID": "FLUID",
                "VALVES": "VALVES"}

Then, create a blank version of the output dictionary.

output = {key:{} for key in set(list_a)}

And finally, update that dict with the values from the other two lists:

for inner_key, val in zip(list_b, list_c):
    for name, real_name in name_mapping.items():
        if inner_key.endswith(name):
            output[real_name][inner_key] = val

That results in this for the lists you presented:

{'FLUID': {'GROUP A FLUID': '46', 'GROUP B FLUID': '47'},
 'MACHINE TOOLS': {'GROUP A MTOOLS': '1',
                   'GROUP B MTOOLS': '2',
                   'GROUP C MTOOLS': '3',
                   'GROUP D MTOOLS': '44'},
 'VALVES': {'GROUP A VALVES': '52', 'GROUP B VALVES': '53'}}

If the values in your lists lined up (e.g. 'MACHINE TOOLS' always appeared at the same index in list_a as something that ended with 'MTOOLS' in list_b), then this solution could be simplified.

Upvotes: 3

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