R：组合/嵌套 if_else 语句

Question

Can anyone tell me what I'm doing wrong here. Trying to use a combined if_else statement in R::dplyr based on the values of two columns. Code below doesn't work - only gives X+90?

Link to csv: https://www.dropbox.com/s/nmyiwdazsvs7wko/VideoTrack_ed.csv?dl=0

library(readr)
library(dplyr)

VidTrack <- read_csv("VideoTrack_ed.csv")

x <- VidTrack$course

Perp <- if_else(("R" %in% VidTrack$Side & VidTrack$course<270), x+90, x-270,
                if_else(("L" %in% VidTrack$Side & VidTrack$course<90), x+270,
                        x-90))
Perp_df <- as.data.frame(Perp)

In Excel this would be; =IF(AND(H2="R",Z2<270),Z2+90,IF(AND(H2="R",Z2>=270),Z2+270,IF(AND(H2="L",Z2<90),Z2+270,Z2-90)))

Column H = VidTrack$Side
Column Z = VidTrack$course

Answer 1

We can use case_when listing all the conditions to be executed sequentially.

library(dplyr)

VidTrack %>%
   mutate(new_column = case_when(
                       Side == "R" & course < 270 ~ course + 90, 
                       Side == "R" & course >= 270  ~ course - 270, 
                       Side == "L" & course < 270 ~ course + 270, 
                       Side == "L" & course >= 90 ~ course - 90))

Answer 2

I am unable to open the file, so can't help much. But, shouldn't it be like this:

Perp <- if_else((VidTrack$Side == "R" & VidTrack$course < 270), x+90, x-270,
                if_else((VidTrack$Side == "L" & VidTrack$course < 90), x+270,
                        x-90))