有序序列的相同元素计数

mylist = ["a","a","b","c","c","c","d","d","d","d","e","f"]
length = len(mylist)
print(length)

i = 0
while i < length:
    times = 1
    passwordstr = mylist[i]
    while i < length-1:
        if mylist[i] == mylist[i+1]:
            times+=1
            i += 1
        else:
            break
    print(times,passwordstr)
    i += 1