How can I create a nested dictionary from existing lists?

Question

I am trying to combine a set of lists into an organized dictionary. The existing lists are in the following format:

index = [1, 2]
keys = [key1, key2, key3]
values_k1 = [a, b, c]
values_k2 = [d, e, f]

I want to organize those lists into the following dictionary:

d = {'1': {'key1':'a','key2':'b','key3':'c'}, '2': {'key1':'d','key2':'e','key3','f'}}

Having separate `values_k1`, `values_k2`, etc. variables makes this difficult, since you have to use variable variables. — Barmar, Jul 15 '21 at 20:44
See https://stackoverflow.com/questions/1373164/how-do-i-create-a-variable-number-of-variables for how to do that — Barmar, Jul 15 '21 at 20:44
@Barmar I'm going to go out on a limb and just guess the OP neglected to make them strings, otherwise, it isn't really (reasonably) possible — juanpa.arrivillaga, Jul 15 '21 at 20:45
@juanpa.arrivillaga I meant the variable names, not the list contents. — Barmar, Jul 15 '21 at 20:47
@juanpa.arrivillaga I assumed there could be a dynamic number of them, e.g. `values_k3`, `values_k4`, etc. — Barmar, Jul 15 '21 at 20:48

flakes · Answer 1 · 2021-07-15T21:21:48.620

d = {
    i: dict(zip(keys, values)) 
    for i, values in zip(index, [values_k1, values_k2])
}

If the index is always incremental you can remove the index array and do something like this:

all_values = [values_k1, values_k2]
d = {
    i: dict(zip(keys, values)) 
    for i, values in enumerate(all_values)
}

And if d always has keys that are incremental you might as well use a list which can be accessed by index value anyways:

all_values = [values_k1, values_k2]
d = [dict(zip(keys, values)) for values in all_values]

score 0 · Answer 2 · answered Jul 15 '21 at 20:46

0

I don't know you should, but you can make a nested dictionary comprehension.

{i:{k:v for k,v in zip(keys,vals)} for i,vals in zip(index,(values_k1, values_k2))}

answered Jul 15 '21 at 20:46

fsimonjetz

2 Answers2