尝试将不同长度的多个文件读入R中的数组

Question

I feel like this is a fairly simple question. I am dealing with 217 different "text" (they're actually .edf files I've converted to text) files, each of which containing a 9 column table of attributes. The data is coming from sensors that were dropped to the ocean floor, so each has a different number of rows. I would like to combine all of these files into one array in R of dimension 9399x9x217. (9399 is the number of rows in the largest file). Currently I'm using this code:

omgdatlist <- list.files(pattern ="*.edf")
named.list <- array(0, dim = c(9399, 9, 217))
for (i in 1:217)
{
named.list[i] <- matrix(assign(omgdatlist[i], read.table(omgdatlist[i], header = FALSE, skip = 51, col.names = c("Time(sec)", "Frame", "Depth(m)", "Temperature(C)", "Conductivity", "Salinity", "Sound Velocity", "Density", "Status"))), nrow = 9399, ncol = 9)
}

However, it's returning a list of 18356247. Is using an array even the most efficient way of doing this?

Answer 1

Because you want to access the ith 2D cell of your array, you need to replace named.list[i] by named.list[,,i] .

Here is a minimum working example:

named.list <- array(0, dim = c(3, 1, 2))
for (i in 1:dim(named.list)[3])
{
  named.list[,,i] <- array(i, dim = c(3, 1))
}
named.list 

which returns

> named.list
, , 1

     [,1]
[1,]    1
[2,]    1
[3,]    1

, , 2

     [,1]
[1,]    2
[2,]    2
[3,]    2

As for efficiency, you might want to look at ?sapply and ?apply .