arrays - Extracting all matrices out of a nested list with varying sublist lengths in R -

i have nested list of matrices. more specifically, have list of matrix lists, each variable number of matrices. extract matrices out of nested lists 1 simple array.

example data ('datlist'):

set.seed(10) dat <- rnorm(n=3*4*6) datmat <- array(dat, dim = c(3,4,6)) datlist <- list() datlist[[1]] <- list() # datmat[,,1] datlist[[1]][[1]] <- datmat[,,1]  datlist[[1]][[2]] <- datmat[,,2]  datlist[[1]][[3]] <- datmat[,,3]  datlist[[2]] <- list() datlist[[2]][[1]] <- datmat[,,4] datlist[[2]][[2]] <- datmat[,,5] datlist[[3]] <- list() datlist[[3]][[1]] <- datmat[,,6]  summary(datlist)  # length class  mode # [1,] 3      -none- list # [2,] 2      -none- list # [3,] 1      -none- list 

the ideal output here above 'datmat' array used create example.

based on answers similar questions, seems apply functions should helpful here, haven't managed them want.

i attempted following loop without success:

  nmats <- sum(as.numeric(summary(datlist)[,1])) # total number of matrices   mats <- array(data = 0, dim = c(3, 4, nmats))   (m in 1:nmats){     (i in 1:length(datlist)) {       (j in 1:length(datlist[[i]])) {         mats[,,m] <- datlist[[i]][[j]]        }      }    } 

all 6 matrices in 'mat' array populated last matrix, amiss indexing. know loop doesn't correct, i'm unsure how else implement it.

in event, either working loop or more concise apply-based solution wonderful.