python - 用数字对字符串中的重复字母进行编码

Question

字符串 'abc' 必须变成 'a1b1c1'。字符串 'aaabcca' - 'a3b1c2a1'

我写了 python 函数，但它无法添加最后一个字母，'abc' 只是 'a1b1'。

string = "aaabbcc"
coded = ''
if len(string) == 0:
   print('')
else:
  count = 1   #start with the first char, not zero!
  prev = string[0]
  for i in range(1,len(string)):
    current = string[i]
    if current == prev:     
       count +=1
    else:              
      coded += prev
      coded += str(count)
      count = 1
      prev = current
      print("coded string: " + coded)
print(coded)

Answer 1

使用itertools.groupby .

>>> from itertools import groupby
>>> s = 'aaabcca'
>>> ''.join('{}{}'.format(c, sum(1 for _ in g)) for c, g in groupby(s))
'a3b1c2a1'

有关 groupby 产生的内容的详细信息:

>>> groups = groupby(s)
>>> [(char, list(group)) for char, group in groups]
[('a', ['a', 'a', 'a']), ('b', ['b']), ('c', ['c', 'c']), ('a', ['a'])]