I have a data frame that has multiple elevations for each date, like the one below. It has over 500,000 entries, so I'd like to collapse the rows into one row for each date and replace the elevation with the mean elevation for that date. How can I do this in R? Thanks for any help!
| Date | Elevation |
|---|---|
| 2007-10-01 | 773.64 |
| 2007-10-01 | 773.66 |
| 2007-10-01 | 773.68 |
| 2007-10-02 | 774.24 |
| 2007-10-02 | 774.25 |
