How to assign an array (two-dimensional list) to a dict in Python?

Question

I want to assign an array (lists in a list) to a dictionary.

For this I have already tried the fromkeys() method. But this is not working as I've expected.

# a list with 3 string elements
list_of_Strings = ['index', 'substance', 'container']
# a list with 3 lists, each list has a few values
index_list = [0,1,2]
substance_list = ['water','oil','acetone']
container_list = ['B100','B200','B300']
list_of_lists = [index_list, substance_list, container_list]

# this line sets all for all dict keys the value to 0
dict_dummy_1 = dict.fromkeys(list_of_Strings,0)

# when I try this line, in every "key value" are all 3 lists from list_of_lists:
# Key -> Value
# index -> index_list, substance_list, container_list
# substance -> index_list, substance_list, container_list
# container -> index_list, substance_list, container_list
dict_dummy_1 = dict.fromkeys(list_of_Strings,list_of_lists)

# but I want to have it like this:
# Key -> Value
# index -> index_list
# substance -> substance_list
# container -> container_list

# with a loop it is possible:
dict_dummy_2 = dict.fromkeys(list_of_Strings,0)
for i in range(len(list_of_Strings)):
    dict_dummy_2[list_of_Strings[i]] = list_of_lists[i]

It is possible to avoid the loop solution? Is there any function for it? Thank you very much in advance. :)

can you add your final output – sahasrara62 Jul 31 '19 at 13:09 — sahasrara62, Jul 31 '19 at 13:09

yukashima huksay · Accepted Answer · 2019-07-31T13:13:50.053

3

Here is a simple oneliner using zip:

dict(zip(list_of_Strings,list_of_lists))

edited Jul 31 '19 at 13:13

answered Jul 31 '19 at 13:05

yukashima huksay

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score 1 · Answer 2 · answered Jul 31 '19 at 13:05

1

You can use a dict-comprehension:

{list_of_Strings[i]: list_of_lists[i] for i in range(len(list_of_Strings))}

answered Jul 31 '19 at 13:05

Carsten

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or `{key: value for key, value in zip(list_of_Strings, list_of_lists)}` – h4z3 Jul 31 '19 at 13:08

score 0 · Answer 3 · answered Jul 31 '19 at 13:12

# a list with 3 string elements
list_of_Strings = ['index', 'substance', 'container']
# a list with 3 lists, each list has a few values
index_list = [0,1,2]
substance_list = ['water','oil','acetone']
container_list = ['B100','B200','B300']
list_of_lists = [index_list, substance_list, container_list]


res = {i:j for i,j in zip(list_of_Strings, list_of_lists)}

print(res)

output

{'index': [0, 1, 2],
 'substance': ['water', 'oil', 'acetone'],
 'container': ['B100', 'B200', 'B300']}

How to assign an array (two-dimensional list) to a dict in Python?

3 Answers3