Dplyr :: rowwise, mutate and NA error

Question

I am trying to use rowwise and mutate with a function that can return NA, but I get an error. Consider this contrived example (which, obviously, does not apply to the workaround, but illustrates the error):

It works:

 library(dplyr) data.frame(k=rnorm(10)) %>% mutate(l = ifelse(k > 0, 1, NA)) kl 1 -1.40223573 NA 2 1.47581873 1 3 0.35938746 1 4 0.87240448 1 5 -0.61991535 NA 6 -1.88152820 NA 7 0.25837350 1 8 -0.02250385 NA 9 0.92757943 1 10 0.49023792 1 

But this gives an error:

 library(dplyr) data.frame(k=rnorm(10)) %>% rowwise() %>% mutate(l = ifelse(k > 0, 1, NA)) Error: incompatible types, expecting a numeric vector 

Answer 1

Note: I registered github issue # 1448 regarding an error as a result of this answer.

Updated October 29, 2015 . It looks like this error in rowwise() fixed. See the link above for more details.

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Firstly, there is no reason to do this in different ways.

As for the error, then NA is a logical type. You will need to use NA_real_ in your ifelse() call on this line. Or, as Ben Bolker notes in the comments below, you can wrap ifelse() with as.numeric() .

 data.frame(k = rnorm(10)) %>% rowwise() %>% mutate(l = ifelse(k > 0, 1, NA_real_)) # Source: local data frame [10 x 2] # Groups: <by row> # # kl # (dbl) (dbl) # 1 -1.7105691140 NA # 2 -0.0702667985 NA # 3 -0.5505724960 NA # 4 -0.7444839870 NA # 5 -0.0005646999 NA # 6 -0.3702584194 NA # 7 0.2596026787 1 # 8 0.4149810662 NA <-- error here pointed out by David A (see comments) # 9 -0.4698540654 NA # 10 1.0961705022 1 

Note that you can also use integers, as in

 mutate(l = ifelse(k > 0, 1L, NA_integer_)) 

But you cannot mix logics and reals / integers in different ways. It seems that