I want to combine two variables into one with a date format

Question

I have a data set with a character column for months (MONTH) and a numeric column indicating years (YEAR). In order to work with it as panel data, I ne

Answer 1

If you wish to use a full-on Tidyverse solution, consider this combination of tidyr, and lubridate's parse_date_time:

library(tidyverse)
df <- tibble::tribble(
  ~STATE,      ~MONTH,      ~YEAR,   ~VALUE,
"California",     "JAN",      2018,      800,
"California",     "FEB",      2018,      780,
"California",     "MAR",      2018,      600,
"Minesota",       "JAN",      2018,      800,
"Minesota",       "FEB",      2018,      780,
"Minesota",       "MAR",      2018,      600)

df %>%
   tidyr::unite(TIME, c(MONTH, YEAR), sep = "-") %>%
   dplyr::mutate(TIME = lubridate::parse_date_time(TIME, "my"))
#> # A tibble: 6 x 3
#>   STATE      TIME                VALUE
#>                       
#> 1 California 2018-01-01 00:00:00   800
#> 2 California 2018-02-01 00:00:00   780
#> 3 California 2018-03-01 00:00:00   600
#> 4 Minesota   2018-01-01 00:00:00   800
#> 5 Minesota   2018-02-01 00:00:00   780
#> 6 Minesota   2018-03-01 00:00:00   600

Also check out the following related question: Converting year and month ("yyyy-mm" format) to a date?