display format of xts when time is 00:00

How can I change the format of the return value of last if the time of that time step is 00:00?

Here is an example

I have two xts objects containing hourly observations with different end times that I want to align.

library(xts)x <- c(1:10)dt <- seq.POSIXt(from = as.POSIXct("2023-06-14 15:00", tz = "GMT"), by = "hour", length.out = 10)x <- xts(x, order.by=dt)y <- c(1:12)dt <- seq.POSIXt(from = as.POSIXct("2023-06-14 15:00", tz = "GMT"), by = "hour", length.out = 12)y <- xts(y, order.by=dt)

If I print x I get

x                    [,1]2023-06-14 15:00:00    12023-06-14 16:00:00    22023-06-14 17:00:00    32023-06-14 18:00:00    42023-06-14 19:00:00    52023-06-14 20:00:00    62023-06-14 21:00:00    72023-06-14 22:00:00    82023-06-14 23:00:00    92023-06-15 00:00:00   10

and when printing y I get

y                        [,1]2023-06-14 15:00:00    12023-06-14 16:00:00    22023-06-14 17:00:00    32023-06-14 18:00:00    42023-06-14 19:00:00    52023-06-14 20:00:00    62023-06-14 21:00:00    72023-06-14 22:00:00    82023-06-14 23:00:00    92023-06-15 00:00:00   102023-06-15 01:00:00   112023-06-15 02:00:00   12

This is all good so far. However, if use last to determine the end of the time series I get a format of the date without time whereas this is not the case when determine the last entry of y:

last(index(x)) [1] "2023-06-15 GMT"last(index(y))[1] "2023-06-15 02:00:00 GMT"

If I now do the following, y is not subsetted by the extend of x, probably because of the time format:

y[paste(first(index(x)), last(index(x)), sep="/")]                        [,1]2023-06-14 15:00:00    12023-06-14 16:00:00    22023-06-14 17:00:00    32023-06-14 18:00:00    42023-06-14 19:00:00    52023-06-14 20:00:00    62023-06-14 21:00:00    72023-06-14 22:00:00    82023-06-14 23:00:00    92023-06-15 00:00:00   102023-06-15 01:00:00   112023-06-15 02:00:00   12