如何在一个循环中获取多个矩阵并自动分配它们？

Question

I have a list containing 15 different groups that I want to convert into 15 different matrices in a for loop. However, I could not make it work.

a=split(datalist,as.factor(datalist$groups))

When I do this I can visualize different groups by typing a[1] a[2] etc. my each a component (a[1], a[2] etc) were in a list and have size of 3x24 and they were considered as non-numeric. I get these components after using split command. but I need them as numeric that is why I thought I need to convert them into matrices and for that, I try to make a loop which converts those components into 15 different matrices which are 3x24 in size.

for each i number (from 1 to 15) I can get a matrix by using

matrix(unlist(a[i]), ncol=columnlength,byrow=rowlength)

this command.

Then I start my loop

    for (i in 1:15) {
  b[i]=matrix(unlist(a[i]), ncol=24,byrow=3)

    }

It is wrong since I am using b[i] which specifies only one unit of a matrix. But I do not know what to use instead of b[i].

Answer 1

I can't understand your problm.

a=split(datalist,as.factor(datalist$groups))

the "a" result is an vector or matrix|data.frame?

then you crate "b" matrix, 3x24

you want put every "a" element into "b" matrix, right?

your "a" have 24 elements with 3 element each? (like a matrix...)

b <- as.matrix(a)

cannot resolve your problem?

Answer 2

Here's an approach I show using mtcars

First, split like you're already doing

split.df <- split(mtcars, mtcars$cyl)

Then, create new variables labeled a thru letters[N]

newnames <- letters[1:length(split.df)]

Use assign to <- the variable name and data

for (x in 1:length(newnames)) {
      assign(newnames[x], as.matrix(split.df[[x]]))
}