CODEWITHSUNDEEP
r
Robin
Robin

Reputation: 159

How to flip N percent of enreries of binary matrix in R?

I have binary matrix A and I want to randomly change 20 percent of zero entries of it to 1. Can someone can help me with this?

Upvotes: 0

Views: 40

Answers (3)

Gopala
Gopala

Reputation: 10473

Try this:

m <- matrix(seq(1:100), nrow = 20, ncol = 5)
m[sample(length(m), round(length(m) * 0.2))] <- 0

Upvotes: 2

akrun
akrun

Reputation: 886948

We can try

i1 <- m1==0
m1[sample(which(i1), round(sum(i1)*0.20))] <- 1

data

set.seed(24)
m1 <- matrix(sample(0:1, 5*4, replace=TRUE), ncol=5)

Upvotes: 2

Rentrop
Rentrop

Reputation: 21497

You can try the following:

Test data

set.seed(42)
dat <- sample(0:1, 40, replace = TRUE)
mat <- matrix(dat, nrow = 5) # 5x8 sample Matrix

Actual code

ind <- which(mat == 0) # Gives you the indices of all zeros in the matrix
ind_to_change <- sample(ind, floor(length(ind)*0.2)) # sample 20% of the indices
mat[ind_to_change] <- 1 # set the samples indices to 1

Upvotes: 2

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