Formatting Hours and Minutes on x-axis with Plotly in R

Question

I am relatively new to using Plotly and am having some issues with formatting my plots.

I have a data frame (which I have summarized from my original data):

df$time_of_eating_occasion_hhmm <- chron(times = df$time_of_eating_occasion_hhmm)
df$rounded_eating_time <- round(df$time_of_eating_occasion_hhmm, "01:00:00")

df %>%
  select(intake_day_of_the_week, intake_day_cat, time_of_eating_occasion_hhmm, rounded_eating_time, total_sugars_gm) %>%
  group_by(intake_day_cat, rounded_eating_time) %>%
  summarize(m = mean(total_sugars_gm)) %>%
  arrange(match(intake_day_cat, c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday")), rounded_eating_time)

The data looks like:

 intake_day_cat rounded_eating_time     m
   <chr>          <times>             <dbl>
 1 Monday         00:00:00             8.40
 2 Monday         01:00:00             6.82
 3 Monday         02:00:00            12.4 
 4 Monday         03:00:00             7.47
 5 Monday         04:00:00             9.11
 6 Monday         05:00:00             7.95
 7 Monday         06:00:00             7.48
 8 Monday         07:00:00             7.23
 9 Monday         08:00:00             7.50
10 Monday         09:00:00             7.66

Where m is grouped by every 30 minutes, by day of the week.

When I pipe my data to plotly, it seems to want to format the x-axis as decimals (0 - 1) as portions of a day, but I want the x-axis to reflect the half hour increments in the "rounded_eating_time" column. Does anyone have any advice on what I should do?

plot_ly(x = ~rounded_eating_time, y = ~m) %>%
  add_lines(color = ~intake_day_cat) %>%
  layout(
    xaxis = list(
      type = 'time',
      tickformat = "%H:%M:%S"
  ))

I have tried using "array" type for tickmode option but it did not change anything. Any advice is appreciated!

Answer 1

Update: It turns out that converting time objects like mine, which were just in hours, minutes, and seconds (HH:MM:SS) into datetimes in R work better in formatting time series ticks in Plotly. This is the code that I used, which worked in formatting my x-axis.

'''

df$eating_time <- as.POSIXct(df$time_of_eating_occasion_hhmm, format = "%H:%M:%S")

df %>%
 select(intake_day_of_the_week, intake_day_cat, time_of_eating_occasion_hhmm, eating_time, !! rlang::sym(x)) %>%
 mutate(eating_time = format(round(eating_time, units="hours"), format="%H:%M")) %>%
 group_by(intake_day_cat, eating_time) %>%
 summarize(m = mean(!! rlang::sym(x))) %>%
 arrange(match(intake_day_cat, 
              c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday")),
        eating_time)