python - 在给定列表中创建重复元素的新列表

Question

我希望我的程序获取一个已经创建的列表，遍历它并检查是否有任何重复的元素。然后创建一个仅包含重复元素的新列表。

def repeated_elements(data):
    repeats = []
    for element in data:
        result = data.count(element)
        if result > 1:
            repeats.append(element)
       return data
print (repeated_elements([1, 2, 3, 1, 3]))#should print out [1, 3, 1, 3]
print (repeated_elements([1, 2, 3, 4, 5]))# should print out []
print (repeated_elements([5, 5, 5, 5, 5]))# should print out [5, 5, 5, 5, 5]
print (repeated_elements([10, 9, 10, 10, 9, 8]))# should print out [10, 9, 10, 10, 9]

程序最终打印出起始集

Answer 1

通过使用 collections.Counter 实现此目的的更好方法列表理解表达式为:

>>> from collections import Counter
>>> my_list = [1, 2, 3, 1, 3]

>>> my_counter = Counter(my_list)
>>> [i for i in my_list if my_counter[i]>1]
[1, 3, 1, 3]