Count occurrences of item in Python list
David Y.
The Problem
How do I count the occurrences of an item in a Python list?
The Solution
We can use the Python list.count method, as below:
products = ["Apple", "Orange", "Banana", "Pear", "Apple", "Banana"] banana_count = products.count("Banana") # => 2
If we need to count the occurrences of every unique item in the list, it is more performant to use the Counter collection from the built-in Python collections library than to use the count method in a loop.
from collections import Counter products = ["Apple", "Orange", "Banana", "Pear", "Apple", "Banana"] element_counts = Counter(products)
This will produce a Counter object, which is a subclass of dict. For the code above, element_counts will look like this:
Counter({"Apple": 2, "Orange": 1, "Banana": 2, "Pear": 1})
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