方法一：用内置方法isdigit()判断数字，isspace()判断空格，isalpha()判断字母，然后格式化输出

 1 def str_count(msgs):
 2     letter_count = 0
 3     num_count = 0
 4     space_count = 0
 5     other_countd = 0
 6     context = ''
 7     str_sum = len(msgs)
 8     for msg in msgs:
 9         if msg.isdigit():
10             num_count += 1
11         elif msg.isspace():
12             space_count += 1
13         elif msg.isalpha():
14             letter_count += 1
15         else:
16             other_count += 1
17     context = "该字符串有字母{letter}个，数字{num}个，空格{space}个，其他符号{other}个".format(letter = letter_count,
18                                                                                                num = num_count,
19                                                                                                space = space_count,
20                                                                                                other = other_count)
21     return context
22 
23 #msgs = 'hello world,123456,Change the world by program!'
24 msgs = input("请输入字符串：")
25 print(str_count(msgs))