Replace NA's by column (value) specific condition

[Jerry]

df <- data.frame(CAR = c(1,1,3,9,1),
BIKE = c(2,NA,4,NA,9),
PLANE = c(8,NA,6,7,9),
BOAT = c(1,2,NA,4,NA),
SCOOTER = c(2,3,6,9,NA))

Hi, I have a df like this. I will like to replace NA values across every row where ‘CAR’ has a value of 1 only; so you get something like this

NEW_df <- data.frame(CAR = c(1,1,3,9,1),
BIKE = c(2,0,4,NA,9),
PLANE = c(8,0,6,7,9),
BOAT = c(1,2,NA,4,0),
SCOOTER = c(2,3,6,9,0))

I know to replace NA’s across the whole dataset, but cant get around this. Any help on this please.

[joels]

Here's one option. In the code below we use across to mutate every column except CAR. We use the replace function to set the desired condition and replacement value.

library(tidyverse)

df <- data.frame(CAR = c(1,1,3,9,1),
                 BIKE = c(2,NA,4,NA,9),
                 PLANE = c(8,NA,6,7,9),
                 BOAT = c(1,2,NA,4,NA),
                 SCOOTER = c(2,3,6,9,NA))

df.new = df %>% 
  mutate(across(-CAR, ~ replace(., is.na(.) & CAR==1, 0)))

NEW_df <- data.frame(CAR = c(1,1,3,9,1),
                     BIKE = c(2,0,4,NA,9),
                     PLANE = c(8,0,6,7,9),
                     BOAT = c(1,2,NA,4,0),
                     SCOOTER = c(2,3,6,9,0))

identical(df.new, NEW_df)
#> [1] TRUE