Combining more than 2 columns by removing NA's in R

Question

At first sight this seems a duplicate of Combine/merge columns while avoiding NA? but in fact it isn\'t. I am dealing sometimes with more than two columns instead of just tw

Answer 1

You can use apply and na.exclude

DF
##   V1 V2 V3 V4 V5
## 1  1 NA NA 13 NA
## 2 NA NA 10 NA 18
## 3 NA  7 NA 15 NA
## 4  4 NA NA 16 NA

t(apply(DF, 1, na.exclude))
##      [,1] [,2]
## [1,]    1   13
## [2,]   10   18
## [3,]    7   15
## [4,]    4   16

If you want to keep the dimensions of the data.frame same, you can use sort with na.last=TRUE instead. This will also take care of cases where you have unequal number of values in different rows.

t(apply(DF, 1, sort, na.last = T))
##      [,1] [,2] [,3] [,4] [,5]
## [1,]    1   13   NA   NA   NA
## [2,]   10   18   NA   NA   NA
## [3,]    7   15   NA   NA   NA
## [4,]    4   16   NA   NA   NA