CODEWITHSUNDEEP
r
WetlabStudent
WetlabStudent

Reputation: 2606

How to write a list of an arbitrary number of functions

suppose I have data X, an n x m matrix, and an n-vector, time, fed into a function. In this function I want to create functions

fun1 = approxfun(time, X[,1], rule=2)
fun2 = approxfun(time, X[,2], rule=2)

. . .

funm = approxfun(time, X[,m], rule=2)

Ideally if there was something like apply that could apply approxfun, that would be great but I couldn't get apply to work. I have looked into paste and parse but I have been told that a major tenant of R is to avoid parse. List seems promising because you can make a list of functions, if there was a function that worked liked rbind or cbind does on matrices only for lists that might do the trick, but because m is arbitrary I am kind of stuck here. I'm really sorry if something similar has been asked before and I missed it.

Upvotes: 1

Views: 72

Answers (1)

baptiste
baptiste

Reputation: 77096

I don't know where you went wrong with apply, it should work fine

x <- matrix(rnorm(40), ncol=4)
time <- 1:10

lfun <- apply(x, 2, approxfun, x = time, rule = 2, method="linear")

# using those functions in plots
time2 <- seq(1, 10, length=100)
par(mfrow=c(2,2))
for(ii in 1:4){
  plot(time, x[,ii])
  lines(time2, lfun[[ii]](time2))
}

Upvotes: 5

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