CODEWITHSUNDEEP
pythonpython-3.xdictionary
mariposard
mariposard

Reputation: 21

How can I count how many keys have a certain value in a dictionary?

I have a dictionary looking something like this:

d = {'f1': ['a','a','b','c'],
     'f2': ['b','c','d'],
     'f3': ['a','c','d']}

I want to get information about how many keys have a certain value. For example: a:2, b:1, c:3... (And if value was in one key more than once, count only first one). Is there a way to do it? Everything I found was about comparing two dictionaries, but here I have one. I searched a lot but I haven't found solution for case like this. Thank you in advance for your help!

Upvotes: 1

Views: 692

Answers (3)

user8273956
user8273956

Reputation:

Define a function genMap in your code, it will do the job

d = {
  'f1': ['a', 'a', 'b', 'c'],
  'f2': ['b', 'c', 'd'],
  'f3': ['a', 'c', 'd']
}

def genMap(obj):
  final_map = {}

  for key in obj:
    already_mapped = []
    for value in d[key]:
      if(value not in already_mapped):
        already_mapped.append(value)
        if(value not in final_map):
          final_map[value] = 0
        final_map[value] += 1
  return final_map

result = genMap(d)
print(result)

Output

{
  'a': 2,
  'b': 2,
  'c': 3,
  'd': 2
}

Upvotes: 2

kabanus
kabanus

Reputation: 26005

Slow one liner:

>>> {k:sum(1 for l in d.values() if k in l) for k in set(sum(d.values(), []))}
{'a': 2, 'd': 2, 'b': 2, 'c': 3}

Upvotes: 3

MehmedB
MehmedB

Reputation: 1147

This may not be the best way but is this what you are looking for?

d = {'f1': ['a','a','b','c'],'f2': ['b','c','d'],'f3': ['a','c','d']}
certain_value = 'a'
counter = 0
for key, value in d.items():   
    if certain_value in value:
        counter += 1
    print("{0} has the {1} for {2} times.".format(key, certain_value, counter))
    counter = 0

Upvotes: 2

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