24 lines
620 B
Markdown
24 lines
620 B
Markdown
---
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title: frequencies
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tags: list,intermediate
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---
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Creates a dictionary with the unique values of a list as keys and their frequencies as the values.
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- Use `collections.defaultdict()` to store the frequencies of each unique element.
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- Use `dict()` to return a dictionary with the unique elements of the list as keys and their frequencies as the values.
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```py
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from collections import defaultdict
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def frequencies(lst):
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freq = defaultdict(int)
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for val in lst:
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freq[val] += 1
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return dict(freq)
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```
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```py
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frequencies(['a', 'b', 'a', 'c', 'a', 'a', 'b']) # { 'a': 4, 'b': 2, 'c': 1 }
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```
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