How to set custom date ticks/breaks in plotly

Question

I'm trying to set custom ticks for specific dates on the x axis. So far I've tried:

• setting the breaks on ggplot (however, after wrapping with ggplotly, breaks next to the edges disappear)
• setting the breaks on ggplotly in several ways (using tickmode array, rangebreaks, etc.) with no luck. Plotly documentation shows how to:
• set custom ticks, but not in date format
• work with time series, but not how to set custom breaks
• display custom ticks at custom locations, but I need labels to be the actual dates of the required locations
• set tick0 and dtick for regular custom ticks, though I need irregular ones

The closer I got to what I want was using the code shown below. However, the first tick I need won't show (the dates I want to use as breaks/ticks can be found in rangebreaks):

    df <- tibble(
  name = c("pat", "bill", "chuck", "dick", "ted"),
  uni = factor(c("DM", "DM", "DM", "VM", "VM")),
  cond =factor(c( "D", "E", "D", "E", "D")),
  f_des = as.Date(c( "2021-07-28", "2021-11-05", "2022-02-02", "2021-07-30", "2022-03-10")),
  f_ces = as.Date(c( "2021-11-04", "2022-01-15", "2022-04-10", "2022-03-10", "2022-04-10"))
)

#plot
ggplot(df, aes(fill = cond, text = name)) + 
  geom_rect(aes( xmin = f_des, xmax = f_ces,
                 ymin = as.numeric(uni) - .6 / 2, ymax = as.numeric(uni) + width / 2)) +
  scale_y_continuous(breaks = seq(levels(df$uni)), labels = levels(df$uni), expand = c(0.01,0))

ggplotly(tooltip = c("text")) %>%
  layout(xaxis = list( 
    rangebreaks = list(values= c( "2021-07-30","2021-10-07","2021-11-05","2022-02-02")),
                       tickcolor="crimson", gridcolor="crimson"))

Here's the ouptut: plot screenshot with less ticks/grids than expected

Answer 1

There are probably more straightforward options but one option would be to first define your desired date breaks and convert them to proper Date objects.

For the tickvals convert the breaks to numerics, for the ticktext format the breaks in your desired format:

library(plotly)

width <- .9

breaks <- as.Date(c("2021-07-30", "2021-10-07", "2021-11-05", "2022-02-02"))
ticktext <- format(breaks, "%b %d")
tickvals <- as.numeric(breaks)

p <- ggplot(df, aes(fill = cond, text = name)) +
  geom_rect(aes(
    xmin = f_des, xmax = f_ces,
    ymin = as.numeric(uni) - .6 / 2, ymax = as.numeric(uni) + width / 2
  )) +
  scale_y_continuous(breaks = seq(levels(df$uni)), labels = levels(df$uni), expand = c(0.01, 0))

ggplotly(tooltip = c("text")) %>%
  layout(xaxis = list(
    ticktext = ticktext,
    tickvals = tickvals,
    tickcolor = "crimson", 
    gridcolor = "crimson"
  ))