程序：

letter_num = 0     
blank_num = 0     
figure_num = 0     
other_num = 0     
a = input('请输入一行字符：')     
for i in a:
    if i.isalpha():
        letter_num += 1
    elif i.isspace():
        blank_num += 1
    elif i.isdigit():
        figure_num += 1
    else:
        other_num += 1
print("输入的字符中，字母的个数为{0}，空格的个数为{1}，数字的个数为{2}，其他字符的个数为{3}".format(letter_num, blank_num, figure_num, other_num))

结果：

请输入一行字符：vrd15 *&$ji4 张 佰 威 jiu7gr8

输入的字符中，字母的个数为13，空格的个数为5，数字的个数为5，其他字符的个数为3