Convert a matrix to a list of vectors in R

Question

What is the most elegant way of converting a matrix to a list, where each element of the list is a vector containing the elements in a row of the matrix?

score 6 · Accepted Answer · answered May 13 '13 at 06:05

6

A couple of approaches

Assuming your matrix is called foo

lapply(seq_len(nrow(foo)), function(x) foo[x,])

or less efficiently.

lapply(apply(foo,1,list), unlist)

answered May 13 '13 at 06:05

mnel

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score 3 · Answer 2 · answered May 13 '13 at 09:11

3

Just for the fun of it, here's the shortest syntax I could think of:

split(x, 1:nrow(x))

Or using the plyr package:

aaply(x, 1, list)

These are slower than @mnel's solutions though (especially the aaply() one).

answered May 13 '13 at 09:11

Ciarán Tobin

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or alply(foo, 1) would do it – mdsumner May 13 '13 at 09:44
Nice. Seems to be faster too. Still way slower than using `lapply()` though (or even `split()`). – Ciarán Tobin May 13 '13 at 10:03

Convert a matrix to a list of vectors in R

2 Answers2