Python · Theory

list.count()

Theory

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list.count() works on a list. Lists can change. Many methods update the same list (append, pop, sort, insert) instead of returning a new one.

list.count() — output — 2. How many times 2 appears.

Trap for list.count() — append([1, 2]) nests a list. extend([1, 2]) adds 1 and 2. sort vs sorted is a viva favourite.

Diagram

index →  0       1       2
  list  → [Asha,  Ravi,  Neha]

Exam tip

In place or new list? Say it first, then one example.

# list.count()
print([1, 2, 2, 3].count(2))

list.count() — output: 2. How many times 2 appears.