ggplot - Custom format for plot axis of time variable

Question

How to define custom format for time variable axis in ggplot2?

DF <- data.frame(TIME = c(350,400,250,650,500,750),
                 CATEGORY = c(1:6))


ggplot(data=DF, aes(x=CATEGORY, y=as_datetime(TIME))) +
  geom_col() +
  scale_y_datetime(labels = date_format("%M:%S"))

What I want is to remove leading zero at the minute-part. Something like this:

Thanks for your time & effort!

Answer 1

Try this:

library(ggplot2)
library(lubridate)
library(scales)
DF <- data.frame(TIME = c(350,400,250,650,500,750),
                 CATEGORY = c(1:6))


date_lab <- function(x) {
  paste0(minute(x), ":", format(x, "%S"))
}

ggplot(data=DF, aes(x=CATEGORY, y=as_datetime(TIME))) +
  geom_col() +
  scale_y_datetime(labels = date_lab)

^{Created on 2020-03-24 by the reprex package (v0.3.0)}