R cell selection using apply

Question

i'm trying to select specific cell from a matrix (data) a change the value to 1

i got those 2 vector

data <- matrix(0,300,300)
X <- c(1,5,87,987,67)
Y <- c(5,7,12,456,99)

x1 and y1 (i.e 1,5) indicate the position i want to select in my matrix

I dont want to select (x1,y2)

I have done what i want to do with:

for (i in 1:length(x)){
  data[x[i],y[i]]<-1
}

i'm pretty sure i can do the same thing with apply which could work faster

Thanks for your help

Answer 1

cbind X and Y and assign the value

data[cbind(X, Y)]  <- 1

#     [,1] [,2] [,3] [,4] [,5]
#[1,]    0    1    0    0    0
#[2,]    0    0    0    0    0
#[3,]    0    0    1    0    0
#[4,]    0    0    0    1    0
#[5,]    0    0    0    0    0

data

Using smaller dataset

X <- c(1,3,4)
Y <- c(2,3,4)
data <- matrix(0, ncol = 5, nrow = 5)

data
#     [,1] [,2] [,3] [,4] [,5]
#[1,]    0    0    0    0    0
#[2,]    0    0    0    0    0
#[3,]    0    0    0    0    0
#[4,]    0    0    0    0    0
#[5,]    0    0    0    0    0