from collections import Counter
def insert_by_occurrence(lst):
count_dict = Counter(lst)
result = []
for item, count in count_dict.most_common():
for i in range(count):
result.append(item)
return result
该函数先使用Counter计算每个元素出现的次数,然后按照出现次数从大到小遍历count_dict,将元素插入到结果列表result中。这样,最先出现的元素会在最前面,而最后出现的元素会在最后面。