判断是否为数字：str.isdigit()
方法1：
list1 = [1,1,2,2,2,2,3,3,3] list2 = set(list1) for i in list1: list1.count(i)
方法2:
from collections import Counter Counter(list1)
方法3：
d = {} for i in list1: if list1.count(i)>1: d[i] = list1.count(i)
基本都有用到字典来实现。