Add new variable with for loop and if statements in R -

let's assume have data set 2 variables, , b, b's a's, not a's b's.

a<-rbind(1,1,1,1,1) b<-rbind(0,0,0,1,1) d<-cbind(a,b) d       [,1] [,2] [1,]    1    0 [2,]    1    0 [3,]    1    0 [4,]    1    1 [5,]    1    1 

i want create new third variable condense information single data frame. attempted writing loop 1 in nrows, if variable 1 write 2, , if b variable 1 write 1

e<- (i in 1:nrow(d)) {     if (d[,1]==1) {         e$new[,i] <- 2     } # end if 1     else (d[,2]==1)     e$new[,i]<-1         } # end 2  } # end 

i want output such:

> d        [,1] [,2] [,3]  [1,]    1    0    2  [2,]    1    0    2  [3,]    1    0    2  [4,]    1    1    1  [5,]    1    1    1 

i keep getting error: error in e$new[, i] <- 0 : incorrect number of subscripts on matrix in addition: warning messages: 1: in 1:x : numerical expression has 2 elements: first used 2: in if (d[, 1] == 1) { : condition has length > 1 , first element used

any debugging script appreciated!

to make things easier, converted matrix data frame

a<-rbind(1,1,1,1,1) b<-rbind(0,0,0,1,1) d<-as.data.frame(cbind(a,b)) 

this makes operations easier (if necessary, can use as.matrix(data_frame) convert matrix)

here loop came with

for(i in 1:nrow(d)){     if((d[i,1] == 1 & d[i,2] == 0) == true){         d$v3[i] <- 2     }else if((d[i,2] == 1) == true){         d$v3[i] <- 1     } } 

what believe happening want test condition 1 element equal one, operation returns vector. therefore, altered condition adding row , column subscript , making boolean.

another possibility achieve result expecting use ifelse command in following way

##this recreate data frame remove(list = ls()) a<-rbind(1,1,1,1,1) b<-rbind(0,0,0,1,1) d<-as.data.frame(cbind(a,b)) d$v3 <- ifelse(d$v1 == 1 & d$v2 == 0, 2,1)