Convert matrix of lists to data.frame

Question

I've got this structure tbl that has the form:

> tbl

     a_1   a_2  a_3
 [1,] "L"  "14" "L"
 [2,] "L"  "62" "D"
 [3,] "H"  "0"  "L"

this is a matrix, actually:

> class(tbl)
[1] "matrix"

but when I attempt to change this into a data.frame , all the entries of the df are displaying only the datatype, like so:

>as.data.frame(tbl, nrow = length(tbl[,1]), ncol = 3, byrow = TRUE)

a_1           a_2         a_3
<list>       <list>      <list>
<chr[1]>    <chr[1]>    <chr[1]>
<chr[1]>    <chr[1]>    <chr[1]>
<chr[1]>    <chr[1]>    <chr[1]>

I have tried a number of options but none of them seem to work including:

data.frame(rows=rownames(tbl)[row(tbl)],vars=colnames(tbl)[col(tbl)], values=c(tbl))

but I receive an error when I try to use it. I would like the resulting data.frame to take the form:

a_1           a_2         a_3
<char>       <chr>      <char>
"L"           "14"        "L"
"L"           "62"        "D"
"H"           "0"         "L"

I looked for similar q's but couldn't find anyone who had this same issue. Any advice would be a great help!

---

dput(tbl)

structure(list("L", "L", "H", "14", "62", "0", "L", "D", "L"), .Dim = c(3L, 3L), .Dimnames = list(NULL, c("a_1", "a_2", "a_3")))


str(tbl)

List of 9
 $ : chr "L"
 $ : chr "L"
 $ : chr "H"
 $ : chr "14"
 $ : chr "62"
 $ : chr "0"
 $ : chr "L"
 $ : chr "D"
 $ : chr "L"
 - attr(*, "dim")= int [1:2] 3 3
 - attr(*, "dimnames")=List of 2
  ..$ : NULL
  ..$ : chr [1:3] "a_1" "a_2" "a_3" 

Answer 1

Try this one-liner:

as.data.frame(apply(tbl, 2, unlist))

or this:

tbl2 <- unlist(tbl)
attributes(tbl2) <- attributes(tbl)
DF <- as.data.frame(tbl2)