Oh sorry. It was a bit late when I wrote that and I see now I was too brief.
I needed a factor to work with so I created a factor called xx with :
xx <- as.factor("2020-10-12")
Do
class(xx)
or
str(xx)
to see that is, in fact a factor.
We cannot directly convert a factor to a date. So first we convert the factor value to a character value using as.character(). Then we apply the ymd() function to convert to date format
to make it a little simpler
## Create factor data
xx <- as.factor("2020-10-12")
## load needed library
library(lubridate)
## Convert factor to character
yy <- as.character(xx)
## convert character data to date
yy <- as.character(xx)
Eh voilà.
Assuming you have a column of data called "xx" in a data.frame or a tibble called "dat1", to make it easy to see what is happening we can do this:
## Convert to character data
yy <- as.character(dat1$xx)
## Covert to date data and replace the old format data with the new date format data in the tibble or data.frame
dat1$xx <- ymd(yy)
Once you are more familiar with R it is just more convenient to it in one line as in:
dat1$xx <- ymd(as.character(dat1$xx)
So, assuming your data column is "Activity2015_2017$ActivityDate" and changing to the lubridate function dmy() to match for data format this should work:
Activity2015_2017$ActivityDate <- dmy(as.character(Activity2015_2017$ActivityDate))
You might find these links useful.
Good luck and welcome to R