How to Create Nested Dictionary in Python with 3 lists

Question

Let us Suppose, I have created 3 lists and I want to create a dictionary for it. e.g.

a= [\'A\', \'B\', \'C\', \'D\']
b =[1, 2, 3, 4]
c = [9, 8, 7, 6]


        

Answer 1

Are you looking for something like this ?

a= ['A', 'B', 'C', 'D']
b =[1, 2, 3, 4]
c = [9, 8, 7, 6]

new_dict={}
set(map(lambda x,y,z:(new_dict.__setitem__(x,{y,z})),a,b,c))
print(new_dict)

output:

{'D': {4, 6}, 'A': {9, 1}, 'B': {8, 2}, 'C': {3, 7}}

Answer 2

You can create the dictionary from zip-ed lists and convert the int values to strings - if I understood your question proper

dct = {x: {str(y): str(z)} for x, y, z in zip(a,b,c)}

Output:

{'A': {'1': '9'}, 'C': {'3': '7'}, 'B': {'2': '8'}, 'D': {'4': '6'}}

Answer 3

a = ['A', 'B', 'C', 'D'] # don't forget the quotation marks
b = [1, 2, 3, 4]
c = [9, 8, 7, 6]

res = dict()
for i, index_a in enumerate(a):
    res[index_a] = {str(b[i]): c[i]}

Edit: Alternatively with list comprehension (mainly for the voters in here, as it's advanced python and harder to understand):

res = dict((a[i], {str(b[i]): c[i]}) for i in range(len(a)))

Answer 4

You can also use map() here:

a = ['A', 'B', 'C', 'D']
b = [1, 2, 3, 4]
c = [9, 8, 7, 6]

dct = dict(map(lambda x, y, z : (x, {str(y): str(z)}), a, b, c))

print(dct)

Which outputs:

{'A': {'1': '9'}, 'B': {'2': '8'}, 'C': {'3': '7'}, 'D': {'4': '6'}}

Answer 5

Assuming what you want is to have a be keys in the outer dictionary, and b and c the key and value element of the inner dicts:

d = {k: {x: y} for k, x, y in zip(a, b, c)}

Update: However, in your example x and y are strings, so if that's what you want:

d = {k: {str(x): str(y)} for k, x, y in zip(a, b, c)}

Answer 6

You can try this:

a= ['A', 'B', 'C', 'D']
b =[1, 2, 3, 4]
c = [9, 8, 7, 6]
new_data = dict([[a, dict([map(str, i)])] for a, i in zip(a, zip(b, c))])

Output:

{'A': {'1': '9'}, 'C': {'3': '7'}, 'B': {'2': '8'}, 'D': {'4': '6'}}

Or

new_data = dict(zip(a, map(lambda x:dict([x]), zip(map(str, b), map(str, c)))))