Reverse datetime (POSIXct data) axis in ggplot previous solution broken - r

Question

A previous post detailed a solution to reversing the time on a ggplot post with this data:
MyData <-
structure(list(Date = structure(c(1492979809.99827, 1492602845.68722,
1493093428.90318, 1492605578.0691, 1492961342.65056, 1492771976.83545,
1493020588.88485, 1493057018.85104, 1492852011.23873, 1492855996.55059
), class = c("POSIXct", "POSIXt")), Value = c(4.52885504579172,
6.0024610790424, 8.96430060034618, 7.06435370026156, 5.08460514713079,
3.47828012891114, 6.29844291834161, 0.898315710946918, 1.44857675535604,
5.74641009094194)), .Names = c("Date", "Value"), row.names = c(NA,
-10L), class = "data.frame")
and this solution:
c_trans <- function(a, b, breaks = b$breaks, format = b$format) {
a <- as.trans(a)
b <- as.trans(b)
name <- paste(a$name, b$name, sep = "-")
trans <- function(x) a$trans(b$trans(x))
inv <- function(x) b$inverse(a$inverse(x))
trans_new(name, trans, inverse = inv, breaks = breaks, format=format)
}
rev_date <- c_trans("reverse", "time")
ggplot(MyData, aes(x=Value, y=Date)) +
geom_point() +
scale_y_continuous(trans = rev_date)
However, when I try and run this code now I get the following error:
Error: Invalid input: time_trans works with objects of class POSIXct only
I am running this code on R version 4.2.2 and cannot find a solution to fix this.
I tried forcing my data into POSIXct format, but the graphing still breaks in the same way.

Answer 1

You could slightly modify the function coord_x_datetime from the tidyquant package to reverse the datetime for your y-axis. Here is the function called coord_y_datetime:
coord_y_datetime <- function(xlim = NULL, ylim = NULL, expand = TRUE) {
if (!is.null(ylim)) {
ylim <- lubridate::as_datetime(ylim)
}
ggplot2::coord_cartesian(xlim = xlim, ylim = ylim, expand = expand)
}
Here is a reproducible example:
library(ggplot2)
ggplot(MyData, aes(x = Value, y = Date)) +
geom_point() +
coord_y_datetime(ylim = c(max(MyData$Date), min(MyData$Date)))
Created on 2022-11-14 with reprex v2.0.2