python dictionary count values per key code example

Example 1: check if key in dictionary python count +1 add if it is

from collections import defaultdict
dct = defaultdict(int)

for key in data:
  dct[key] += 1

# defaultdict(, {'a': 4, 'c': 3, 'b': 2, 'd': 1})

Example 2: get number of key in dictionary python

#Call len(obj) with a dictionary as obj to count the number 
#of key-value pairs in the dictionary.

a_dictionary = {"a": 1, "b": 2}
print(len(a_dictionary))

OUTPUT:
2

Example 3: python counting dictionary

counts = dict()
for i in items:
  counts[i] = counts.get(i, 0) + 1