If you only want a single item’s count, use the count
method:
>>> [1, 2, 3, 4, 1, 4, 1].count(1)
3
Important: this is very slow if you are counting multiple different items
Each count
call goes over the entire list of n
elements. Calling count
in a loop n
times means n * n
total checks, which can be catastrophic for performance.
If you want to count multiple items, use Counter
, which only does n
total checks.