replace NA with 0 and all other values/text as 1

Question

airquality

    Ozone Solar.R Wind Temp Month Day
1      41     190  7.4   67     5   1
2      36     118  8.0   72     5   2
3      12     149 12.6   74     5   3
4             


        

Answer 1

Assuming your dataframe is called airquality

airquality$Ozone <- ifelse(is.na(airquality$Ozone), 0, 1) 

Answer 2

airquality$Ozone <- as.integer(!is.na(airquality$Ozone))

Answer 3

Alternatively

airquality$Ozone[!is.na(airquality$Ozone)] <- 1L
airquality$Ozone[is.na(airquality$Ozone)] <- 0L