工商python编程输入一串字母，输出字母及其出现的个数

输入：abbccd
输出：a1b2c2d1

import re
str_in=input()
str1=list(str_in)
res=[]
for i in str1:
    patten=re.compile(i)
    res.append(patten.findall(str_in))
#print(res)
res1=[]
for i in res:
    if i not in res1:
        res1.append(i)
#print(res1)
count0=[]
for i in res1:
    count0.append(str(len(i)))
#print(count0)
result=[]
for i in range(len(res1)):
    result.append(res1[i][0])
    result.append(count0[i])
print("".join(result))