Summing Rows in Matrices created by lapply

Question

I'm brand new to R and I'm trying to figure out how to sum the rows from the following output.

u <- c(1,2,3)
x <- lapply(u, replicate, rbinom(10,1,.5))

When I do this x is equal to

[[1]]
      [,1]
 [1,]    0
 [2,]    0
 [3,]    1
 [4,]    1
 [5,]    0
 [6,]    1
 [7,]    1
 [8,]    1
 [9,]    1
[10,]    0

[[2]]
      [,1] [,2]
 [1,]    0    1
 [2,]    0    1
 [3,]    1    0
 [4,]    1    1
 [5,]    1    1
 [6,]    1    1
 [7,]    1    1
 [8,]    1    0
 [9,]    1    0
[10,]    0    0

[[3]]
      [,1] [,2] [,3]
 [1,]    1    0    0
 [2,]    1    1    1
 [3,]    1    0    1
 [4,]    1    0    1
 [5,]    0    0    1
 [6,]    0    0    1
 [7,]    0    1    0
 [8,]    1    1    1
 [9,]    0    1    1
[10,]    0    1    1

When I use the coding

rowSums(x)

or

rowSums(x[2])

I get this error

Error in rowSums(x) : 'x' must be an array of at least two dimensions

How can I sum the rows? Also, is there a way to break up the tables so that I can do individual analysis. Preferably a way that is not manual so I can use it if I have 100+ tables

Answer 1

A loop over the individual elements of the list is conveniently performed using lapply(). You could try this:

lapply(x, rowSums)
#[[1]]
# [1] 0 1 0 1 1 0 1 1 1 0
#
#[[2]]
# [1] 2 1 2 2 1 2 1 1 0 1
# 
#[[3]]
# [1] 1 1 2 1 1 0 1 1 1 1

data:

u <- c(1,2,3)
set.seed(123)
x <- lapply(u, replicate, rbinom(10,1,.5))