R: Drawing Arbitrary Partitions on a Graph-CodePudding

The

I want to change the above code so that "x", "xend", "y", "yend" can come from a data frame:

For instance, suppose I have the following data frame:

my_points = data.frame(x1 = c(-40, -41) , x2 = c(20, 21) , y1 = c(-30, -31), y2 = c(50, 51) ) > my_points x1 x2 y1 y2 1 -40 20 -30 50 2 -41 21 -31 51

From here, I would like to make two graphs:

ggplot(data=my_data, aes(x=var_1, y=var_2)) geom_point() geom_segment(aes(x = my_points[1,1], xend = my_points[1,2], y = my_points[1,3], yend = my_points[1,4]), color = "red") geom_segment(aes(x = my_points[1,2], xend = my_points[1,1], y = my_points[1,4], yend = my_points[1,3]), color = "red") geom_segment(aes(x = my_points[1,1], xend = my_points[1,2], y = my_points[1,4], yend = my_points[1,3]), color = "red") geom_segment(aes(x = my_points[1,1], xend = my_points[1,2], y = my_points[1,4], yend = my_points[1,3]), color = "red") ggtitle("graph 1") ggplot(data=my_data, aes(x=var_1, y=var_2)) geom_point() geom_segment(aes(x = my_points[2,1], xend = my_points[2,2], y = my_points[2,3], yend = my_points[2,4]), color = "red") geom_segment(aes(x = my_points[2,2], xend = my_points[2,1], y = my_points[2,4], yend = my_points[2,3]), color = "red") geom_segment(aes(x = my_points[2,1], xend = my_points[2,2], y = my_points[2,4], yend = my_points[2,3]), color = "red") geom_segment(aes(x = my_points[2,1], xend = my_points[2,2], y = my_points[2,4], yend = my_points[2,3]), color = "red") ggtitle("graph 2")

But this is not producing the same result as before:

Furthermore, Graph 2 also does not work:

Can someone please show me how to fix this?

Thanks!

CodePudding user response：

If you will use a data.frame, you cand do everything in a single call of geom_segment.

library(tidyverse) var_1 = rnorm(1000,20,20) var_2 = rnorm(1000,20,20) my_data = data.frame(var_1, var_2) my_points = tibble::tribble( ~rowid, ~x1, ~x2, ~y1, ~y2, "h1", -50, 50, 50, 50, "v1", 50, 50, -50, 50, "h2", -50, 0, 0, 0, "v2", 0, 0, -50, 0 ) ggplot(data = my_data, aes(x = var_1, y = var_2)) geom_point() geom_segment(data = my_points, aes(x = x1, xend = x2, y = y1, yend = y2), color = 'red')

You can use this structure as well, but now you need two geom_segment() calls

my_points2 = tibble::tribble( ~rowid, ~x1, ~y1, ~x2, ~y2, "Segment 1", -50, 50, 50, -50, "Segment 2", -50, 0, 0, -50, ) ggplot(data = my_data, aes(x = var_1, y = var_2)) geom_point() # Horizontal lines geom_segment(data = my_points2, aes(x = x1, y = y1, xend = x2, yend = y1), color = 'red') # Vertical lines geom_segment(data = my_points2, aes(x = x2, y = y2, xend = x2, yend = y1), color = 'red')

CodePudding user response：

OP requested to

Separating out the Rows

If OP wants to separate each pair of half rectangles, you can use faceting or apply an aesthetic to associate with rownames(my_points). For convenience, it might make sense to first create a column in my_points for this purpose, but it is not strictly required.

my_points$graph <- rownames(my_points) p <- ggplot(data=my_data, aes(x=var_1, y=var_2)) geom_point(size=0.6) # vertical lines geom_segment(data=my_points, aes(x=x1, xend=x1, y=-Inf, yend=y1, color=graph)) geom_segment(data=my_points, aes(x=x2, xend=x2, y=-Inf, yend=y2, color=graph)) # horizontal lines geom_segment(data=my_points, aes(x=-Inf, xend=x1, y=y1, yend=y1, color=graph)) geom_segment(data=my_points, aes(x=-Inf, xend=x2, y=y2, yend=y2, color=graph)) theme_bw() p

Extending to more Half Rectangles

We can extend this answer to accommodate a larger dataframe of my_points by adding some additional rows to my_points and using faceting as an example to demonstrate the principles above even further.

# moar points!!!1!1!!111!1! my_points <- rbind( my_points, c(-20, 40, -20, 40), c(-10, 60, -10, 30) ) # adding the column... or just reference color=rownames(my_points) instead. my_points$graph <- rownames(my_points) p <- ggplot(data=my_data, aes(x=var_1, y=var_2)) geom_point(size=0.6, alpha=0.3) # vertical lines geom_segment(data=my_points, aes(x=x1, xend=x1, y=-Inf, yend=y1, color=graph)) geom_segment(data=my_points, aes(x=x2, xend=x2, y=-Inf, yend=y2, color=graph)) # horizontal lines geom_segment(data=my_points, aes(x=-Inf, xend=x1, y=y1, yend=y1, color=graph)) geom_segment(data=my_points, aes(x=-Inf, xend=x2, y=y2, yend=y2, color=graph)) facet_wrap(~graph) theme_bw() p

The key to remember when working this question is to keep track of how to reference x, xend, y and yend in the aesthetics for geom_segment(). OP was referencing those incorrectly in their attempts posted (resulting in the "X" instead of the half-rectangle).