forward fill all missing values for all variables

Question

Consider this simple dataframe

> data_frame(var1 = c(NA, 1 , NA),
+            var2 = c (NA, 3, NA))
# A tibble: 3 x 2
   var1  var2
  <dbl> <dbl>
1    NA    NA
2     1     3
3    NA    NA

I want to fill forward all the missing values for all columns in the dataframe. It seems to me that tidyr::fill() can do that, but I am unable to make it work without specifying the columns one at a time.

> data_frame(var1 = c(NA, 1 , NA),
+            var2 = c (NA, 3, NA)) %>% tidyr::fill(.direction = 'down')
# A tibble: 3 x 2
   var1  var2
  <dbl> <dbl>
1    NA    NA
2     1     3
3    NA    NA

while entering the column name seems to work

> data_frame(var1 = c(NA, 1 , NA),
+            var2 = c (NA, 3, NA)) %>% tidyr::fill(var1, .direction = 'down')
# A tibble: 3 x 2
   var1  var2
  <dbl> <dbl>
1    NA    NA
2     1     3
3     1    NA

what am I missing here? Thanks

Answer 1

tidyr verbs accept dplyr::select column specifications, so you can use everything():

library(tidyverse)

df <- data_frame(var1 = c(NA, 1 , NA),
                 var2 = c (NA, 3, NA))

df %>% fill(everything())
#> # A tibble: 3 x 2
#>    var1  var2
#>   <dbl> <dbl>
#> 1    NA    NA
#> 2     1     3
#> 3     1     3

Answer 2

We can convert the column names to symbols with syms and evaluate (!!!)

d1 %>% 
  tidyr::fill(!!! rlang::syms(names(.)), .direction = 'down')
# A tibble: 3 x 2
#   var1  var2
#  <dbl> <dbl>
#1    NA    NA
#2     1     3
#3     1     3

data

d1 <- data_frame(var1 = c(NA, 1 , NA), var2 = c (NA, 3, NA))