#python121页,4.2,2018,11,6 n=input("请输入一行字符:") a=b=c=d=0 for i in n: if ord('a')<=ord(i)<=ord('z') or ord('A')<=ord(i)<=ord('Z'): a=a+1 elif ord('0')<=ord(i)<=ord('9'): b=b+1 elif ord(i)==ord(' '): c=c+1 else: d=d+1 print("这一行字符中字母的数量是:{},数字的数量是:{},空格数量是:{},其他字符的数量是:{}。".format(a,b,c,d))