How to form the matrix of logical '1' and '0' using two vectors and logical operators in r?

Question

Here is Matlab code to form the matrix of logical values of '0' and '1'

 A=[1 2 3 4 5 6 7 8 9 10  ];
 N = numel(A);
 step = 2;    % Set this to however many zeros you want to add each column
 index = N:-step:1;
 val = (1:N+step).' <= index;

Which result in

 val=

 1     1     1     1     1
 1     1     1     1     1
 1     1     1     1     0
 1     1     1     1     0
 1     1     1     0     0
 1     1     1     0     0
 1     1     0     0     0
 1     1     0     0     0
 1     0     0     0     0
 1     0     0     0     0
 0     0     0     0     0
 0     0     0     0     0

How to do same task in r ,particularly val = (1:N+step).' <= indexthis step?

Answer 1

One option is

i <- seq_len(ncol(m1))
sapply(rev(i), function(.i) {
         m1[,.i][sequence(.i *2)] <- 1
         m1[,.i]
   })
#      [,1] [,2] [,3] [,4] [,5]
# [1,]    1    1    1    1    1
# [2,]    1    1    1    1    1
# [3,]    1    1    1    1    0
# [4,]    1    1    1    1    0
# [5,]    1    1    1    0    0
# [6,]    1    1    1    0    0
# [7,]    1    1    0    0    0
# [8,]    1    1    0    0    0
# [9,]    1    0    0    0    0
#[10,]    1    0    0    0    0
#[11,]    0    0    0    0    0
#[12,]    0    0    0    0    0

---

Or vectorize it

i1 <- rep(i,  rev(2*i))
m1[cbind(ave(i1, i1, FUN = seq_along), i1)] <- 1
m1
#      [,1] [,2] [,3] [,4] [,5]
# [1,]    1    1    1    1    1
# [2,]    1    1    1    1    1
# [3,]    1    1    1    1    0
# [4,]    1    1    1    1    0
# [5,]    1    1    1    0    0
# [6,]    1    1    1    0    0
# [7,]    1    1    0    0    0
# [8,]    1    1    0    0    0
# [9,]    1    0    0    0    0
#[10,]    1    0    0    0    0
#[11,]    0    0    0    0    0
#[12,]    0    0    0    0    0

---

Or another option without creating a matrix beforehand

n <- 5
i1 <- seq(10, 2, by = -2)
r1 <- c(rbind(i1, rev(i1)))
matrix(rep(rep(c(1, 0), n), r1), ncol = n)
#      [,1] [,2] [,3] [,4] [,5]
# [1,]    1    1    1    1    1
# [2,]    1    1    1    1    1
# [3,]    1    1    1    1    0
# [4,]    1    1    1    1    0
# [5,]    1    1    1    0    0
# [6,]    1    1    1    0    0
# [7,]    1    1    0    0    0
# [8,]    1    1    0    0    0
# [9,]    1    0    0    0    0
#[10,]    1    0    0    0    0
#[11,]    0    0    0    0    0
#[12,]    0    0    0    0    0

data

m1 <- matrix(0, 12, 5)