Enriching a ggplot2 plot with multiple geom_segment in a loop?

Question

I successfully create a plot using the following:

# suppose I have a p <- ggplot(data=df, ...) then the following works 
# I get those two segments plotte         


        

Answer 1

An alternative approach would be to avoid using a loop at all. You can pack your segment data up in a separate data.frame from your main data and use aes() to plot everything at once like so:

segment_data = data.frame(
    x = c(1, 5),
    xend = c(1, 5), 
    y = c(103, 103),
    yend = c(107, 107)
)

p = ggplot(df, ...) +
geom_segment(data = segment_data, aes(x = x, y = y, xend = xend, yend = yend))