>>> a = ["aa","bb","cc","aa","dd","ee","aa","aa","ff","aa"] >>> a ['aa', 'bb', 'cc', 'aa', 'dd', 'ee', 'aa', 'aa', 'ff', 'aa'] >>> a.index("aa") ## 返回单元元素的索引 0
>>> c = a.count("aa") >>> c 5
>>> b = -1
>>> for i in range(c): b = a.index("aa",b + 1,len(a)) print("aa",b) ## 返回重复元素的所有索引 aa 0 aa 3 aa 6 aa 7 aa 9