python的list如何去掉重复元素

numbers = [1,7,3,2,5,6,2,3,4,1,5]

new_numbers = []

for x in numbers:

    if x not in new_numbers:

       new_numbers.append(x)

print(new_numbers)

numbers = [1,7,3,2,5,6,2,3,4,1,5]

new_numbers = list(set(numbers))

print(new_numbers)

numbers = [1,7,3,2,5,6,2,3,4,1,5]

new_numbers = list(set(numbers))

new_numbers.sort(key=numbers.index)

print(new_numbers)