loess()函数的预测

Question

我试着只预测两个值，模型是

data(mtcars) #is already available in R

m1 = loess(mtcars$mpg ~ mtcars$cyl + mtcars$disp)
# the prdedict function works well
y.predict <- predict(m1, data.frame(mtcars$cyl, mtcars$disp))

但是它通过使用两个预测器的所有现有值来估计模型m1

mtcars$cyl和mtcar$disp，我只想估计mtcar$mpg的一个值。

我试过了

new.data= data.frame(mtcars$cyl=c(2,3), mtcars$disp=c(200,1000))
y.predict <- predict(m1, new.data)

但它给出了以下警告消息：'newdata‘有2行，但找到的变量有32行

感谢您的帮助

Answer 1

这是符号中的细微差别，可以这样尝试：

data(mtcars) #is already available in R
attach(mtcars) # attach it to the environment so you can use column names directly
m1 = loess(mpg ~ cyl + disp)
# the prdedict function works well
y.predict <- predict(m1, data.frame(cyl, disp))

# add new data
new.data = data.frame(cyl = c(6,8), disp = c(150,100))
y.predict <- predict(m1, new.data)