R tidyverse equivalent to Stata replace if missing

Question

I am trying to find an R/tidyverse equivalent to Stata's replace b = a if missing(b).

Say I have these data:

library(tidyverse)
data <- data.frame(a=c(1:8), b= c(1:5, NA, NA, NA))

I am trying to replace the missing values in b with the values in a. I try this:

data %<>% mutate(b = replace_na(b, a))

But get an error. What can I do in the tidyverse to solve this problem?

Answer 1

The way you're going about it I'd use coalesce from dplyr:

data %<>% mutate(b = coalesce(b, a))

Output:

data

  a b
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
6 6 6
7 7 7
8 8 8