有时候，我们需要在字符串中加入相应的变量，以下提供了几种字符串加入变量的方法：

1、+ 连字符

name = 'zhangsan'
print('my name is '+name)

#结果为 my name is zhangsan

2、% 字符

name = 'zhangsan'
age = 25
price = 4500.225
print('my name is %s'%(name))
print('i am %d'%(age)+' years old')
print('my price is %f'%(price))
#保留指定位数小数(四舍五入)
print('my price is %.2f'%(price))

结果为
my name is zhangsan
i am 25 years old
my price is 4500.225000
my price is 4500.23

3、format()函数

对于变量较多的情况，加入加'+'或者'%'相对比较麻烦，这种情况下可以使用format函数

name = 'zhangsan'
age = 25
price = 4500.225
info = 'my name is {my_name},i am {my_age} years old,my price is {my_price}'\
    .format(my_name=name,my_age=age,my_price=price)
print(info)

结果为：
my name is zhangsan,i am 25 years old,my price is 4500.225