如何创建函数以找到两个向量的索引斜率

Question

I have looked everywhere for this answer but I am having a hard time even figuring our how to ask this question. I am trying to create a function such that it creates a vector that is a function of two other vectors, where I use a for loop to index values at k and k+1. Here is an example of my code, which does not work:

x <- 1:10
y <- x^2

d <- data.frame(x,y)

invSlope <- NULL

invSlope.f <- function(X,Y){
    for(k in 1:length(X)-1){
        invSlope[k] = (X[k+1] - X[k])/ (Y[k+1] - Y[k])
        invSlope[length(X)] = 0
        return(invSlope)
    }
}

d$invSlope <- invSlope.f(d$x,d$y)

What I am trying to accomplish is at d$invSlope[1] I have the inverse of the slope of the line that comes after it (delta x/delta y). The last value of the vector would just be 0. I can accomplish this with a for loop (or even nested for loops), but I would like to generalize this to a function.

Thanks

Answer 1

diff函数是一种矢量化方法...我们不需要“ steenkin”循环：

finvslope <- function(xseq, yseq) { c( diff(xseq)/diff(yseq) , 0) }