I needed to count frequency of items in a list. Given a list like below
some_data = ['a','b','v','c','l','c']
The ugly way was using the dictionary
| frequency_count = dict() | |
| some_data = ['a','b','v','c','l','c'] | |
| for item in some_data: | |
| if item in frequency_count: | |
| frequency_count[item] += 1 | |
| else: | |
| frequency_count[item] = 1 | |
| print frequency_count |
The end result is
{'a': 1, 'c': 2, 'b': 1, 'l': 1, 'v': 1}
But we can use Counter which is much cleaner
| from collections import Counter | |
| cnt = Counter() | |
| some_data = ['a','b','v','c','l','c'] | |
| for item in some_data: | |
| cnt[item] += 1 | |
| print cnt |
Result -
Counter({'c': 2, 'a': 1, 'b': 1, 'l': 1, 'v': 1})
But, more elegant, as suggested in comments by Andy
| from collections import Counter | |
| some_data = ['a','b','v','c','l','c'] | |
| result = Counter(some_data) |
And, another way is using defaultdict
| from collections import defaultdict | |
| some_data = ['a','b','v','c','l','c'] | |
| frequency_count = defaultdict(int) | |
| for item in some_data: | |
| frequency_count[item] += 1 | |
| print frequency_count | |
Result
defaultdict(
You can read more here http://docs.python.org/2/library/collections.html
You can use Counter more elegantly by simply passing it the list:
Counter(some_data)
Awesome!