CODEWITHSUNDEEP
rmatrix
ljohnson
ljohnson

Reputation: 23

If statement to fill Matrix, incorrect number of subscripts

I am trying to write a for loop where if the cell of one matrix matches a letter it then fills a blank matrix with the entire row that matched. Here is my code

mets<-data.frame(read.csv(file="Metabolite_data.csv",header=TRUE))

full<-length(mets[,6])
A=matrix(,nrow=4930,ncol=8, byrow=T)

for (i in 1:full){

  if (mets[i,6]=="A") (A[i,]=(mets[i,]))

}

If I replace the i in the if statement with a single number it works to fill that row of matrix A, however it will not fill more then one row. TIA

Upvotes: 0

Views: 61

Answers (2)

Luke C
Luke C

Reputation: 10291

You might be getting problems going from data frame to matrix. It could be that just using "mets" as a matrix instead of a data frame could solve your problem, or you could use as.matrix within your for loop. An example of the latter with made-up data since I don't have your "metabolite_data.csv":

mets <- matrix(sample(LETTERS[1:4], 80, replace = TRUE), nrow = 10, ncol = 8)
mets <- as.data.frame(mets)

A <- matrix(nrow = nrow(mets), ncol = ncol(mets), byrow = TRUE)

for(i in 1:nrow(mets)){
  if(mets[i,6] == "A"){
    A[i,] = as.matrix(mets[i,])
  }
}

print(A)

Upvotes: 1

Ricardo Fernandes Campos
Ricardo Fernandes Campos

Reputation: 911

You may wanna try to specify ncol=dim(mets)[2] to make sure you are providing same number of inputs to fill the matrix.

Upvotes: 0

Related Questions