I have a class named Individual, and I have a function based on it. When I run I get

---> 13 population: list[Individual], elite_size=0.1, new_pop=0.2

TypeError: 'type' object is not subscriptable

How can I get this to work?

def selection_rank_with_population_replacement_elite(
    population: list[Individual], elite_size=0.1, new_pop=0.2
) -> list[Individual]:

    sorted_individuals = sorted(population, key=lambda ind: ind.get_sharpe(), reverse=True)
    best_n_individuals = int(np.floor(len(sorted_individuals) * elite_size))
    new_individuals = int(np.floor(len(sorted_individuals) * new_pop))
    rank_distance = 1 / len(population)
    ranks = [(1 - i * rank_distance) for i in range(len(population))]
    ranks_sum = sum(ranks)
    selected = sorted_individuals[:best_n_individuals]

    for i in range(len(sorted_individuals) - best_n_individuals - new_individuals):
        shave = random.random() * ranks_sum
        rank_sum = 0
        for i in range(len(sorted_individuals)):
            rank_sum  = ranks[i]
            if rank_sum > shave:
                selected.append(sorted_individuals[i])
                break
    new_individuals = [Individual.create_random() for _ in range(new_individuals)]
    selected.extend(new_individuals)

    return selected

CodePudding user response：

Your code should work with Python 3.9 , but will not work with 3.8 or earlier.

With 3.8, using typing.List instead:

from typing import List

def selection_rank_with_population_replacement_elite(
    population: List[Individual], elite_size=0.1, new_pop=0.2
) -> list[Individual]:

Ref: https://docs.python.org/3/library/typing.html (search for typing.List in there)

[typing.List is] Deprecated since version 3.9: builtins.list now supports [].