CODEWITHSUNDEEP
r
user2462924
user2462924

Reputation: 75

Store a series of vectors in "for loop"

I have a problem of saving a series of vectors (column of matrix) in "for loop" in R. Actually, I want to calculate the mean of some vectors (rows) in a matrix. I ran "for loop" to find out the vectors (columns) I want to find mean for rows of those vectors (columns). I have tried to use "apply" function but what I got is the last vector (column) because I don't know how to save those previous vectors (columns) while running "for loop" in somewhere. Can anybody enlighten me? Thanks. `

column.name<-colnames(loadfile)
       for(i in 1:length(column.name)){
        char<- column.name[i]
        tmp<-agrep("HW", char, ignore.case = TRUE, max.distance = 0.1 )
        if(length(tmp) > 0){ 
        print(column.name[i])
        x<-i
        print(x)
    }
        loadfile$newcol<-apply(loadfile[x],1,mean)
    }

Above code, loadfile is data.frame and I create a new column for saving the average of each row in HW columns. I don't mind show my code.

Upvotes: 1

Views: 1312

Answers (1)

agstudy
agstudy

Reputation: 121568

Very hard to help you without a reproducible example. here I guess just what you want to do. It is vectorized version, since agrep and rowMeans are vectorized.

tmp <- agrep("HW", column.name, ignore.case = TRUE, 
             max.distance = 0.1 )
loadfile$newcol <- rowMeans(loadfile[,tmp])

EDIT I add a reproducible example, and it works fine for a matrix and a data.frame:

mm <- matrix(1:25,ncol=5)
colnames(mm)  <- c(paste0('HW',1:3),paste0('NO',1:2))
loadfile <- as.data.frame(mm)
column.name <- colnames(loadfile)
tmp <- agrep("HW", column.name, ignore.case = TRUE, 
             max.distance = 0.1 )
loadfile$newcol <- rowMeans(loadfile[,tmp])

Upvotes: 3

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