r - How to pad "19" to a string

Question

I have the following dataset.

# A tibble: 30,560 x 3
   fips  year    emp
   <chr> <chr> <dbl>
 1 01001 10     9828
 2 01001 20     6261
 3 01001 30     8172
 4 01001 40     6752
 5 01001 50     5957
 6 01001 60     5818
 7 01001 70     8118
 8 01001 80    12433
 9 01001 90    15432
10 01001 2000  22847
# … with 30,550 more rows

I would like to get the following output.

# A tibble: 30,560 x 3
   fips  year    emp
   <chr> <chr> <dbl>
 1 01001 1910   9828
 2 01001 1920   6261
 3 01001 1930   8172
 4 01001 1940   6752
 5 01001 1950   5957
 6 01001 1960   5818
 7 01001 1970   8118
 8 01001 1980  12433
 9 01001 1990  15432
10 01001 2000  22847
# … with 30,550 more rows

To get this dataset, I wrote the following code. But it would be very tedious. I also try str_pad, but padding "19" could not work. Could you tell me smarter method?

emp %>% 
  mutate(year= ifelse(year == "00", "1900",
              ifelse(year == "10", "1910",
              ifelse(year == "20", "1920", 
              ifelse(year == "30", "1930",
              ifelse(year == "40", "1940",
              ifelse(year == "50", "1950",
              ifelse(year == "60", "1960",
              ifelse(year == "70", "1970",
              ifelse(year == "80", "1980",
              ifelse(year == "90", "1990", 
                     "2000"))))))))))) 

Answer 1

等待大神答复