Filling and completing with tidyr

The following makes use of the packages tidyr and readr. You may need to install them from CRAN using the code install.packages(c("tidyr","readr")) if you want to run this on your computer. (The packages are already installed on the notebook container, however.)

Filling missing values with fill()

library(tidyr)
library(readr)

messy_data_str <- "
country,  year,var1, var2
Rodinia,  1297,  67, -3.0
,         1298,  69, -2.9
,         1299,  70, -2.8
Pannotia, 1296,  73, -4.1
,         1297,  74, -3.9
,         1298,  75, -3.9
Pangaea,  1296,  54, -1.2
,         1297,  53, -1.1
,         1298,  52, -1.0
,         1299,  51, -0.9
"

messy_data_str %>% read_csv() -> messy_data
messy_data

# A tibble: 10 x 4
   country   year  var1  var2
   <chr>    <dbl> <dbl> <dbl>
 1 Rodinia   1297    67  -3  
 2 NA        1298    69  -2.9
 3 NA        1299    70  -2.8
 4 Pannotia  1296    73  -4.1
 5 NA        1297    74  -3.9
 6 NA        1298    75  -3.9
 7 Pangaea   1296    54  -1.2
 8 NA        1297    53  -1.1
 9 NA        1298    52  -1  
10 NA        1299    51  -0.9

messy_data %>% fill(country) -> filled_data
filled_data

# A tibble: 10 x 4
   country   year  var1  var2
   <chr>    <dbl> <dbl> <dbl>
 1 Rodinia   1297    67  -3  
 2 Rodinia   1298    69  -2.9
 3 Rodinia   1299    70  -2.8
 4 Pannotia  1296    73  -4.1
 5 Pannotia  1297    74  -3.9
 6 Pannotia  1298    75  -3.9
 7 Pangaea   1296    54  -1.2
 8 Pangaea   1297    53  -1.1
 9 Pangaea   1298    52  -1  
10 Pangaea   1299    51  -0.9

Completing data by missing values with complete()

filled_data %>% complete(crossing(country,year))

# A tibble: 12 x 4
   country   year  var1  var2
   <chr>    <dbl> <dbl> <dbl>
 1 Pangaea   1296    54  -1.2
 2 Pangaea   1297    53  -1.1
 3 Pangaea   1298    52  -1  
 4 Pangaea   1299    51  -0.9
 5 Pannotia  1296    73  -4.1
 6 Pannotia  1297    74  -3.9
 7 Pannotia  1298    75  -3.9
 8 Pannotia  1299    NA  NA  
 9 Rodinia   1296    NA  NA  
10 Rodinia   1297    67  -3  
11 Rodinia   1298    69  -2.9
12 Rodinia   1299    70  -2.8