An attempt to put date labels on an integer-sequenced x-axis, when there are multiple sequential points per date.

multi_event_dates.R

# Always
options(stringsAsFactors = FALSE)


library(tidyverse)


# Setting the ggplot2 theme
theme_set(theme_bw())


# How many periods of data to generate?
n_quarters <- 10

# Which metrics?
metrics <- c("Gained", "Lost", "Exploded")
n_metrics <- length(metrics)


# Calculate the offsets for each metric to ensure even spacing in the plot
metric_offset <- seq(from = 0, by = 1 / n_metrics, length.out = n_metrics)



# Create a sequence of dates
dates <- seq.Date(Sys.Date(), by = "1 day", length.out = n_quarters)


# Generate the data
testdat <- expand.grid(date = dates, metric = metrics) %>% 
    as.data.frame() %>% 
    arrange(date) %>% 
    
    # Convert dates into integers, then add the offset so each metric has a
    # unique spot on the x-axis
    mutate(x = as.integer(date) + metric_offset,
           y = x + rnorm(n()))
    


# Check the results
testdat




# Plot on the numeric x-axis, but convert to Dates for labeling
# The breaks = ... nonsense is required to ensure that the breaks fall on whole
# integers.
ggplot(testdat, aes(x = x, y = y, color = metric)) +
    geom_point(size = 4) +
    scale_x_continuous(breaks = function(x) { seq(from = floor(x[1]), 
                                                  to = ceiling(x[2]),
                                                  by = 1) },
                       labels = function(x) { as.Date(x, origin = "1970-01-01") })

    




# Here's how I'd go about getting Year-Quarter formatting on x.
# I hadn't thought it through, but you might have to change by = 1 to
# by = 90 or something if the dates are ~90 days apart... ugh.
format_yr_qtr <- function(x) {
    
    x_Date <- as.Date(x, origin = "1970-01-01")
    
    paste(format(x_Date, "%Y"), quarters(x_Date))
          
}


ggplot(testdat, aes(x = x, y = y, color = metric)) +
    geom_point(size = 4) +
    scale_x_continuous(breaks = function(x) { seq(from = floor(x[1]), 
                                                  to = ceiling(x[2]),
                                                  by = 1) },
                       labels = format_yr_qtr)