# [R] R for skip to the next row if condition met and then another condition to check

Tue Dec 6 22:24:44 CET 2016

This might help.

trboot3 <- structure(c(0L, -1L, -1L, -1L, -1L, -1L, -1L, -1L, 0L, 0L, -1L,
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 1L, 1L, 0L, 0L, 0L, 0L,
1L, 1L, 1L, 0L, 0L, 0L, 0L, 0L, -1L, -1L, 0L, 1L, 0L, 0L, -1L,
-1L, -1L, -1L, -1L, -1L, -1L, -1L, -1L, 0L, 0L, 0L, 0L, 0L, 0L,
-1L, 0L, 0L, 0L), .Dim = c(20L, 3L), .Dimnames = list(NULL, c("V7",
"V8", "V9")))

# function to identify first occurrence of successive values in a vector
first <- function (x) {
l <- length(x)
y <- c(1, 1 - (x[-1] == x[-l]))
y==1
}

# start with a matrix of zeroes, the same size as the original
trboot4 <- array(0, dim=dim(trboot3), dimnames=dimnames(trboot3))

# identify the first occurrence of successive values in each column
indx <- apply(trboot3, 2, first)

# replace these first occurrence cells with their original values
trboot4[indx] <- trboot3[indx]

trboot4

V7 V8 V9
[1,]  0  1  0
[2,] -1  0 -1
[3,]  0  0  0
[4,]  0  0  0
[5,]  0  0  0
[6,]  0  0  0
[7,]  0  0  0
[8,]  0  1  0
[9,]  0  0  0
[10,]  0  0  0
[11,] -1  0  0
[12,]  0  0  0
[13,]  0  0  0
[14,]  0  0  0
[15,]  0  0  0
[16,]  0 -1  0
[17,]  0  0 -1
[18,]  0  0  0
[19,]  0  1  0
[20,]  0  0  0

Jean

On Sun, Dec 4, 2016 at 4:08 AM, Ashwini Patil <ash369ster at gmail.com> wrote:

> I have a dataset with many rows and columns. Below is a sample:
>
> V7  V8  V90   1   0-1  1   -1-1  1   -1-1  0   -1-1  0   -1-1  0
> -1-1  0   -1-1  1   -10   1   -10   1   -1-1  0   00   0   00   0   00
>   0   00   0   00   -1  00   -1  -10   0   00   1   00   0   0
>
> This data is saved in a matrix trboot3 What I want to do is create a loop
> whereby two conditions are checked and data is altered.
>
>    1. If there is a zero, skip to the next row.
>    2. If there is same number one below another in a row, keep the first
>    number and change the rest to zero.
>
> Here is my code for the above loop:
>
> trboot4<-trboot3
> valboot<-length(trboot3[,1])for (k in 1:length(trboot3[1,])){
>   for (i in 2:valboot-1){
>     if (trboot3[k,i]==0) {i<-i+1}
>     else{
>       if(trboot3[k,i] == trboot3[k,i+1]){
>         for (j in i+1:valboot){ if(trboot3[k,j] ==
> trboot3[k,i]){trboot4[k,j]<-0}else{break}
>           if(j==valboot){break}
>         }
>       }
>     }
>   }}
>
> I want to save the new matrix in trboot4
>
> basically the above sample should become:
>
> V7  V8  V90   1   0-1  0   -10   0   00   0   00   0   00   0   00   0
>   00   1   00   0   00   0   0-1  0   00   0   00   0   00   0   00
> 0   00   -1  00   0   -10   0   00   1   00   0   0
>
>
> Thank you!
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help