If cells in a column are empty, fill with cells from another column

[Pauler]

Hey there,

I want to overlap columns in such a way that empty cells in column A are filled by entries from column B in the corresponding cell. Thanks for your help!

Best regards, Paula

[Equation]

library(tidyverse)

overlap <- tibble(
  col_A = c(1, 2, 3, NA, NA),
  col_B = c(10, 20, 30, 40, 50)
)

overlap %>% 
  mutate(col_A = ifelse(is.na(col_A), col_B, col_A))
#> # A tibble: 5 × 2
#>   col_A col_B
#>   <dbl> <dbl>
#> 1     1    10
#> 2     2    20
#> 3     3    30
#> 4    40    40
#> 5    50    50

[Pauler]

Thanks for your help! I've used your Code but there is still an error "error in (function (..., row.names = NULL, check.rows = FALSE, check.names = TRUE, :
arguments imply differing number of rows: 46, 986184"

[Equation]

Could you provide a small reprex/example of your code and the data you are using?

[nirgrahamuk]

What you asked, implies that both columns are in the same data.frame, but the error message you shared (to my mind at least) challenges that assumption). Can you confirm if your two source columns are in the same data.frame, or are you wanting to merge data.frames as an earlier step ?

[Dylan_Marczak]

Is there a function like fill() that will fill horizontally rather than vertically?