遇到的问题

a = input('请输入a')
b = input('请输入b')
print(a,'*',b,'=',a*b)

发生异常: TypeError can't multiply sequence by non-int of type 'str'

问题：输入的数据类型为str，不能直接进行运算

解决：计算时以int将str的字符定义为整数

a = input('请输入a')
b = input('请输入b')
print(a,'*',b,'=',int(a)*int(b))

Final Project

s1 = int(input('The score for Last year'))
s2 = int(input('The score for the year'))
r = 100*(s2-s1)/s1
if r>=0:
    r = r
    print('The score {0} {1:.1f}%'.format('increase', r))
else:
    r = -r
    print('The score {0} {1:.1f}%'.format('decrease',r))

存疑

a=abc
print(a)

发生异常: NameError name 'abc' is not defined

a='abc'
print(a)

为什么赋值为字符需要引号，而数字不需要？