Filling missing value in group

Question

I have data frame where some of the values are missing

A 1
A NA
A NA
B NA
B 2
B NA
C NA
C NA
C NA

How can I fill in groups where I have data?

Answer 1

You can also use fill from tidyr:

library(dplyr)
library(tidyr)

df1 %>%
  group_by(ID) %>%
  fill(v1) %>%
  fill(v1, .direction = "up")

Result:

# A tibble: 9 x 2
# Groups:   ID [3]
     ID    v1
  <chr> <int>
1     A     1
2     A     1
3     A     1
4     B     2
5     B     2
6     B     2
7     C    NA
8     C    NA
9     C    NA

Credits to @akrun for dput