Python报错：IndexError: string index out of range

import string
s = input('输入：')
letter = 0
space = 0
digit = 0
other = 0
i = 0
print(len(s))
#print(s[2])
while i <= len(s):
    c = s[i]
    i+=1
    if c.isalpha():
        letter+=1
    elif c.isspace():
        space+=1
    elif c.isdigit():
        digit+=1
    else :
        other +=1

print('字母有%d个,空格有%d个,数字有%d个,其他有%d个'%(letter,space,digit,other))
    

代码功能为：输入一行字符，分别统计出其中英文字母、空格、数字和其它字符的个数。

出现以下报错：

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-40-b0902d128a40> in <module>()
      9 #print(s[2])
     10 while i <= len(s):
---> 11     c = s[i]
     12     i+=1
     13     if c.isalpha():

IndexError: string index out of range

分析：典型的字符串的索引越界。while循环是到<=len(s)。如字符串长度是10 ，s[10]实际不存在。因为是从0开始的啊。

处理方法：改为whilei < len(s):