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Python – Convert List to Index and Value dictionary
  • Last Updated : 02 Sep, 2020
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Given a List, convert it to dictionary, with separate keys for index and values.

Input : test_list = [3, 5, 7, 8, 2, 4, 9], idx, val = “1”, “2”
Output : {‘1’: [0, 1, 2, 3, 4, 5, 6], ‘2’: [3, 5, 7, 8, 2, 4, 9]}
Explanation : Index and values mapped at similar index in diff. keys., as “1” and “2”.

Input : test_list = [3, 5, 7], idx, val = “1”, “2”
Output : {‘1’: [0, 1, 2], ‘2’: [3, 5, 7]}
Explanation : Index and values mapped at similar index in diff. keys., as “1” and “2”.

Method : Using loop + enumerate()

In this, we iterate for list elements using enumerate() to get index along with values, and append the values and indices accordingly in separate dictionaries accordingly.



Python3




# Python3 code to demonstrate working of 
# Convert List to Index and Value dictionary
# Using loop + enumerate()
  
# initializing list
test_list = [3, 5, 7, 8, 2, 4, 9]
  
# printing original list
print("The original list is : " + str(test_list))
  
# initializing keys for index and vals 
idx, val = "indx", "vals"
  
# initializing empty mesh
res = {idx : [], val : []}
for id, vl in enumerate(test_list):
    res[idx].append(id)
    res[val].append(vl)
          
# printing results
print("Constructed dictionary : " + str(res))
Output
The original list is : [3, 5, 7, 8, 2, 4, 9]
Constructed dictionary : {'indx': [0, 1, 2, 3, 4, 5, 6], 'vals': [3, 5, 7, 8, 2, 4, 9]}

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