Answer to Question #253151 in Python for Phikem

Question

def invert_dict(d):

   inverse = dict()

   for key in d:

      val = d[key]

     if val not in inverse:

        inverse[val] = [key]

     else:

        inverse[val].append(key)

   return inverse 

Modify this function so that it can invert your dictionary. In particular, the function will need to turn each of the list items into separate keys in the inverted dictionary. 

Run your modified invert_dict function on your dictionary. Print the original dictionary and the inverted one. 

Include your Python program and the output in your Learning Journal submission. 

Describe what is useful about your dictionary. Then describe whether the inverted dictionary is useful or meaningful, and why. 

Answer 1

def invert_dict(d):
    inverse = dict()
    for key in d:
        val = d[key]
        for v in val:
            if v not in inverse:
                inverse[v] = [key]
            else:
                inverse[v].append(key)
    return inverse




my_dict = {1:['a','b','c'],
           2:['d','a','b'],
           3:['c','d','a'],
           4:['b','c','d']}
invert_dict = invert_dict(my_dict)


print('original dictionary:\n', my_dict, sep='')
print('inverted dictionary:\n', invert_dict, sep='')