ggplot2 plot points when y value in NA - r

Question

I have a dataframe where the x value (discrete) is present and want to include on the x-axis in the plot; however, its y value is NA
I still want to show the x value even though y is NA. Is there a way to do this in ggplot2?
Currently, it simply skips the first two rows that has the NA value.
ggplot(tChartDF()[['df']], aes(
x = factor(tChartDF()[['df']][['Rare event date']], levels = unique(tChartDF()[['df']][['Rare event date']])),
y = unlist(tChartDF()[['df']][['days_between']]),
)) +
geom_hline(yintercept = unlist(tChartDF()[['timeScaleCL']]), color = input$tChartCLColour, lwd = input$tChartCLWidth) +
geom_hline(yintercept = unlist(tChartDF()[['timeScaleUL']]), linetype = 'dashed', lwd = 1, color = 'red') +
geom_hline(yintercept = unlist(tChartDF()[['timeScaleLL']]), linetype = 'dashed', lwd = 1, color = 'red') +
scale_x_discrete(expand = c(0,0)) +
theme_classic() +
geom_line(aes(group = 1), lwd = input$tChartLineWidth, color= input$tChartLineColour) +
geom_point(size = input$tChartMarkerSize, color = input$tChartMarkerColour) +
labs(title = input$tChartPlotTitle, x = input$tChartPlotXLabel, y = input$tChartPlotYLabel) +
theme(
plot.title = element_text(size = 24, face = 'bold', family = 'Arial', hjust = 0.5),
plot.margin = margin(0, 1, 0, 0, "cm"),
axis.title = element_text(size = 20, face = 'bold', family = 'Arial'),
axis.text = element_text(size = 16, face = 'bold', family = 'Arial'),
axis.text.x = element_text(angle = as.numeric(input$tChartXOrientation), vjust = 0.5),
axis.ticks.length = unit(.25, 'cm'),
) +
coord_cartesian(clip = 'off')
As seen, it only starts plotting at date: 2022/12/15 (ignoring the previous values in the table) columns y and mr have the NA values.
For the plot, I only care about the first two columns (Rare events and days_between). I tried selecting only those two columns and plotting but it still ignores the first two rows.
Desired result:

Answer 1

If we start with something like
mt <- mtcars
mt$mpg[c(3,6,9)] <- NA
and plot the line as in
ggplot(mt, aes(disp, mpg)) +
geom_line()
we don't see the missing points (not a surprise). We can add them this way:
transform(mt, mpg2 = ifelse(is.na(mpg), max(mpg, na.rm = TRUE) + 1, mpg)) |>
ggplot(aes(disp, mpg)) +
geom_line() +
geom_point(aes(y = mpg2), data = ~ subset(., is.na(mpg)), shape = 1)
This can easily be adapted to be at the bottom, using different shapes/colors, perhaps even on an explicitly-gray background (top/bottom ribbon).