Inverting a dictionary with list values

Question

So, I have this index as a dict.

index = {\'Testfil2.txt\': [\'nisse\', \'hue\', \'abe\', \'pind\'], \'Testfil1.txt\': [\'hue\', \'abe\', 
\'tosse\', \'svend         


        

Answer 1

I've tried around and you want to use val not in inverse but it can't be checked if a "list is in a dict". (val is a list)

For your code a simple change will do what you want:

def invert_dict(d): 
    inverse = dict() 
    for key in d: 
        # Go through the list that is saved in the dict:
        for item in d[key]:
            # Check if in the inverted dict the key exists
            if item not in inverse: 
                # If not create a new list
                inverse[item] = [key] 
            else: 
                inverse[item].append(key) 
    return inverse