list of lists with different lengths to data.frame in R

Question

I have read many answers in SO about converting list of lists to df. But, I have noticed that they all have the length of lists (within the main big list) to be the same. I

Answer 1

Here's one way:

R> as.data.frame(as.matrix(h1))
                            V1
USA             10, 13, 17, 11
RUSSIA                    NULL
BRAZIL                    NULL
CHINA        11, 11, 10, 8, 12
TAIWAN 12, 9, 9, 11, 9, 12, 14
CHILE                     NULL

R> as.data.frame(as.matrix(h1))['TAIWAN', ]
$TAIWAN
[1] 12  9  9 11  9 12 14

Answer 2

You can convert a list to a matrix, where every element of the matrix will be a list.

d1 <- data.frame(country_name=names(h1), list=matrix(h1))

That said, I recommend against doing this because it does not fit the R paradigm. Most R functions assume a matrix contains elements from one atomic type.