# Value frequencies

Canonical: https://www.wiki.jodisand.me/snippets/python/frequencies/


Creates a dictionary with the unique values of a list as keys and their frequencies as the values.

- Use `collections.defaultdict` to store the frequencies of each unique element.
- Use `dict()` to return a dictionary with the unique elements of the list as keys and their frequencies as the values.

```py
from collections import defaultdict

def frequencies(lst):
  freq = defaultdict(int)
  for val in lst:
    freq[val] += 1
  return dict(freq)
```

```py
frequencies(['a', 'b', 'a', 'c', 'a', 'a', 'b']) # { 'a': 4, 'b': 2, 'c': 1 }
```