Try this:
myfile %>% mutate(V5 = (V1 == 1 & V2 != 4) + 2 * (V2 == 4 & V3 != 1))
giving:
V1 V2 V3 V4 V5 1 1 2 3 5 1 2 2 4 4 1 2 3 1 4 1 1 0 4 4 5 1 3 0 5 5 5 5 4 0
or this:
myfile %>% mutate(V5 = ifelse(V1 == 1 & V2 != 4, 1, ifelse(V2 == 4 & V3 != 1, 2, 0)))
giving:
V1 V2 V3 V4 V5 1 1 2 3 5 1 2 2 4 4 1 2 3 1 4 1 1 0 4 4 5 1 3 0 5 5 5 5 4 0
Note
Suggest you get a better name for your data frame. myfile makes it seem as if it holds a file name.
Above used this input:
myfile <- structure(list(V1 = c(1L, 2L, 1L, 4L, 5L), V2 = c(2L, 4L, 4L, 5L, 5L), V3 = c(3L, 4L, 1L, 1L, 5L), V4 = c(5L, 1L, 1L, 3L, 4L )), .Names = c("V1", "V2", "V3", "V4"), class = "data.frame", row.names = c("1", "2", "3", "4", "5"))
Update 1 Since originally posted dplyr has changed %.%
to %>%
so have modified answer accordingly.
Update 2 dplyr now has case_when
which provides another solution:
myfile %>% mutate(V5 = case_when(V1 == 1 & V2 != 4 ~ 1, V2 == 4 & V3 != 1 ~ 2, TRUE ~ 0))