R list of lists to data.frame

Question

I\'ve got a list of lists, call it listHolder, which has length 5.

Every element in listHolder is a list of numeric data, with 160 or so e

Answer 1

This is the easiest solution I've found.

library(jsonlite)
library(purrr)
library(data.table)

dt_list <- map(list_of_lists, as.data.table)
dt <- rbindlist(dt_list, fill = TRUE, idcol = T)

dt

Answer 2

I think this is easier than the previous solutions:

mydf = data.frame(x1 = c('a', 'b', 'c'))
mylist = list(c(4, 5), c(4, 5), c(4, 5))
mydf$x2 = mylist
print(mydf)
  x1   x2
1  a 4, 5
2  b 4, 5
3  c 4, 5

Answer 3

The value of nrow needs to be fixed. I fixed your code as follows:

dd  <-  as.data.frame(matrix(unlist(listHolder), nrow=length(unlist(listHolder[1]))))

Answer 4

This achieves a similar result, but is more intuitive (to me at least)

#Generate fake data 
listoflists=list(c(1,'a',3,4),c(5,'b',6,7))

#Convert to a dataframe, transpose, and convert the resulting matrix back to a dataframe
df= as.data.frame(t(as.data.frame(listoflists)))

#Strip out the rownames if desired
rownames(df)<-NULL

#Show result
df

Answer 5

AS @dimitris_ps mentioned earlier, the answer could be:

do.call(rbind, listHolder)

Since do.call naturally "strips" 1 level of the "list of list", obtaining a list, not a list of lists.

After that, rbind can handle the elements on the list and create a matrix.