I'd like to to convert a list of numeric vectors into a single matrix with different length of columns.
This is the structure of the list, each "Name" is a element of the list :
$ Name 1 : num [1:5] 3 3 4 0 5
$ Name 2 : num [1:4] 3 2 4 0
$ Name 3 : num [1:7] 3 3 4 0 5 4 4
$ Name 4 : num [1:7] 3 1 4 0 5 5 4
I expect this result:
| Name 1 | Name 2 | Name 3 | Name 4 |
|---|---|---|---|
| 3 | 3 | 3 | 3 |
| 3 | 2 | 3 | 1 |
| 4 | 4 | 4 | 4 |
| 0 | 0 | 0 | 0 |
| 5 | NA | 5 | 5 |
| NA | NA | 4 | 5 |
| NA | NA | 4 | 4 |
How can I build this matrix ? Thank you in advance
You have to bring all list elements to the same length using length<- and then cbind it to get a matrix.
do.call(cbind, lapply(L, `length<-`, max(lengths(L))))
# Name 1 Name 2 Name 3 Name 4
#[1,] 3 3 3 3
#[2,] 3 2 3 1
#[3,] 4 4 4 4
#[4,] 0 0 0 0
#[5,] 5 NA 5 5
#[6,] NA NA 4 5
#[7,] NA NA 4 4
Data
L <- list("Name 1" = c(3, 3, 4, 0, 5),
"Name 2" = c(3, 2, 4, 0),
"Name 3" = c(3, 3, 4, 0, 5, 4, 4),
"Name 4" = c(3, 1, 4, 0, 5, 5, 4))
# create a list of numeric vectors
mylist <- list(Name1 = c(3, 3, 4, 0, 5),
Name2 = c(3, 2, 4, 0),
Name3 = c(3, 3, 4, 0, 5, 4, 4),
Name4 = c(3, 1, 4, 0, 5, 5, 4))
# find the maximum length of the vectors in the list
max_len <- max(sapply(mylist, length))
# create an empty matrix of appropriate dimensions
my_matrix <- matrix(NA, nrow = max_len, ncol = length(mylist))
# fill in the matrix with the values from the list
for (i in seq_along(mylist)) {
vec <- mylist[[i]]
n <- length(vec)
my_matrix[1:n, i] <- vec
}
# add column names
colnames(my_matrix) <- names(mylist)
# print the resulting matrix
my_matrix
Name1 Name2 Name3 Name4
[1,] 3 3 3 3
[2,] 3 2 3 1
[3,] 4 4 4 4
[4,] 0 0 0 0
[5,] 5 NA 5 5
[6,] NA NA 4 5
[7,] NA NA 4 4
max_len = max(lengths(l))
matrix(
unlist(
lapply(l, function(x) {
c(x, rep(NA, max_len - length(x)))
})
), ncol = length(l)
)
