How do I extract parts of a cell inside an R dataframe to save them in a different column?

Question

I need to extract the year from vote_data and save it into another column to finally sort the dataframe by year.

Anyone with an idea? If it is possible to sort it without extracting, that would be even better. Already tried sorting, but did not find out how to sort only by year when the cell contains the whole date.

It's . asier to help you if you include a simple [reproducible example](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) with sample input and desired output that can be used to test and verify possible solutions. Please [do not post code or data in images](https://meta.stackoverflow.com/q/285551/2372064) — MrFlick, Nov 08 '22 at 15:57

score 1 · Answer 1 · answered Nov 08 '22 at 15:56

1

We could do

library(dplyr)
library(lubridate)
df1 <- df1 %>% 
    mutate(year = year(ymd(vote_date))) %>%
    arrange(year)

answered Nov 08 '22 at 15:56

akrun

874,273
37
540
662

score 0 · Accepted Answer · answered Nov 08 '22 at 16:00

0

You are looking for arrange() from the dplyr package:

df = data.frame(
       vote_id = 1:3,
       vote_date = c("1975-04-25","1976-04-25","1974-04-25")
)

dplyr::arrange(df, df$vote_date)
dplyr::arrange(df, desc(df$vote_date)) # Descendent

answered Nov 08 '22 at 16:00

Laura

24
1

score -1 · Answer 3 · answered Nov 08 '22 at 15:54

-1

Check out the lubridate package, I believe it has the functions you're looking for!

answered Nov 08 '22 at 15:54

Holly

11
2

2

Please avoid [link only answers](https://meta.stackexchange.com/questions/8231/are-answers-that-just-contain-links-elsewhere-really-good-answers/8259#8259). Try to include enough information to be able to help the user should the link ever disappear. – MrFlick Nov 08 '22 at 15:59

How do I extract parts of a cell inside an R dataframe to save them in a different column?

3 Answers3