CODEWITHSUNDEEP
r
Seen
Seen

Reputation: 4194

Combine lists in a list

I have a list like 

$`1`
[1] 1959   13

$`2`
[1] 2280  178   13

$`3`
[1] 2612  178   13

$`4`
[1] 2902  178   13

And the structure is something like: 

structure(list(`1` = c(1959, 13), `2` = c(2280, 178, 13), `3` = c(2612, 
178, 13), `4` = c(2902, 178, 13)......,.Names = c("1", "2", "3", "4"....)

How can I combine the lists within this list and produce a list like:

$`list`
[1] 1959   13
[2] 2280  178   13
[3] 2612  178   13
[4] 2902  178   13

Upvotes: 0

Views: 272

Answers (2)

Tyler Rinker
Tyler Rinker

Reputation: 109844

This is the closest I can get to what you're asking for as a matrix:

LIST <- structure(list(`1` = c(1959, 13), `2` = c(2280, 178, 13), `3` = c(2612, 
178, 13), `4` = c(2902, 178, 13)))

cbind.fill <-
function(...) {
    nm <- list(...)
    nm<-lapply(nm, as.matrix)
    n <- max(sapply(nm, nrow))
    do.call(cbind, lapply(nm, function(x) rbind(x, 
        matrix(, n - nrow(x), ncol(x)))))
}

t(do.call('cbind.fill', LIST))
print(X$list, na.print="", quote=FALSE)

Or using plyr

LIST <- lapply(LIST, function(x) data.frame(t(x)))
library(plyr)
rbind.fill(LIST)

Maybe you just don't want names ?

If so...

names(LIST) <- NULL
LIST

I think I just don't get the output structure you're after.

Upvotes: 4

Edward
Edward

Reputation: 5537

Try the following code. The problem is that I'm not too sure what you want as your output; you're calling it a list but it looks an awful lot like matrix. Assuming that you do want it as a matrix, the following should do the trick:

x <- list()
x$`1` <- c(1959, 13)
x$`2` <- c(2280, 178, 13)
x$`3` <- c(2612, 178, 13)
x$`4` <- c(2902, 178, 13)

# maximum number of elements in any vector
max <- max(sapply(x, function(y) length(y)))

# make all vectors the same length
x <- lapply(x, function (y){length(y) <- max; y})

# combine them in a matrix
result <- do.call(rbind, x)

result:

> result
  [,1] [,2] [,3]
1 1959   13   NA
2 2280  178   13
3 2612  178   13
4 2902  178   13

You can always save this matrix output as an element of a list. I got the idea to make the lengths equal from here.

You won't be able to get rid of the NA if you want your matrix to be numeric (you can always turn it into characters and make the NA be "", but it's probably not a good idea for further work with the matrix).

It may be that I'm confused and that you want a list after all, but as Josh mentioned in his comment, your data is correct to begin with in that case.

Upvotes: 0

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