Remove unwanted letter in data column names in R environment

I have a dataset the contains a large number of columns every column has a name of date in the form of x2019.10.10

what I want is to remove the x letter and change the type of the date to be 2019-10-10

How this could be done in the R environment?

One solution would be:

1. Get rid of x
2. Replace . with -.

Here I create a dataframe that has similar columns to yours:

df = data.frame(x2019.10.10 = c(1, 2, 3),
                x2020.10.10 = c(4, 5, 6))
df

  x2019.10.10 x2020.10.10
1           1           4
2           2           5
3           3           6

And then, using dplyr (looks much tidier):

library(dplyr)
names(df) = names(df) %>% 
        gsub("x", "", .) %>% # Get rid of x and then (%>%):
        gsub("\\.", "-", .) # replace "." with "-"
df

  2019-10-10 2020-10-10
1          1          4
2          2          5
3          3          6

If you do not want to use dplyr, here is how you would do the same thing in base R:

names(df) = gsub("x", "", names(df))
names(df) = gsub("\\.", "-", names(df))
df

  2019-10-10 2020-10-10
1          1          4
2          2          5
3          3          6