CODEWITHSUNDEEP
rfunctionloops
Justine Oesterle
Justine Oesterle

Reputation: 3

Creating new matrix from output values of a function in r?

Hi I have made a function Get to calculate the mean and SD from a data set, I have seven data sets of the same format and want to put the output applying the Get function to these data sets in one matrix to compare. I know I need one more step in my function but cannot figure it out? Also id there away to loop this over each data set automatically if the names are CA1, CA2, ...? I am new to R

This is the function 

 Get <- function (x) {
  x <- as.matrix(x)
  m <- mean(x[,3:4])
  SD <- sd(x[,3:4])
  return(list(mean=m, SD=SD))
}

Upvotes: 0

Views: 100

Answers (1)

akrun
akrun

Reputation: 887028

Try:

 set.seed(42) #creating some datasets
 CA1 <- as.data.frame(matrix(sample(1:20, 5*20, replace=TRUE), ncol=5))
 CA2 <- as.data.frame(matrix(sample(1:20, 5*20, replace=TRUE), ncol=5))
 CA3 <- as.data.frame(matrix(sample(1:20, 5*20, replace=TRUE), ncol=5))

 nm1 <- ls(pattern="^CA\\d")
 res <- sapply(mget(nm1), Get)
 res #here you get a list of `6`
 #     CA1      CA2      CA3     
 #mean 10.1     9.9      9.275   
 #SD   6.058687 5.490318 5.579208

To convert to matrix

 m1 <- matrix(unlist(res), ncol=3, dimnames=dimnames(res))
 m1
 #         CA1      CA2      CA3
 #mean 10.100000 9.900000 9.275000
 #SD    6.058687 5.490318 5.579208

Upvotes: 1

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