(This article was first published on

So perhaps you have all figured this out already, but I was excited to figure out how to finally neatly get all the data frames, lists, vectors, etc. out of a nested list. It is as easy as nesting calls to the apply family of functions, in the case below, using plyr's apply like functions. Take this example:**Recology**, and kindly contributed to R-bloggers)# Nested lists code, an example

# Make a nested list

mylist <- list()

mylist_ <- list()

for(i in 1:5) {

for(j in 1:5) {

mylist[[j]] <- i*j

}

mylist_[[i]] <- mylist

}

# return values from first part of list

laply(mylist_[[1]], identity)

[1] 1 2 3 4 5

# return all values

laply(mylist_, function(x) laply(x, identity))

1 2 3 4 5

[1,] 1 2 3 4 5

[2,] 2 4 6 8 10

[3,] 3 6 9 12 15

[4,] 4 8 12 16 20

[5,] 5 10 15 20 25

# perform some function, in this case sqrt of each value

laply(mylist_, function(x) laply(x, function(x) sqrt(x)))

1 2 3 4 5

[1,] 1.000000 1.414214 1.732051 2.000000 2.236068

[2,] 1.414214 2.000000 2.449490 2.828427 3.162278

[3,] 1.732051 2.449490 3.000000 3.464102 3.872983

[4,] 2.000000 2.828427 3.464102 4.000000 4.472136

[5,] 2.236068 3.162278 3.872983 4.472136 5.000000

Created by Pretty R at inside-R.org

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