Stored/flexible geom

Question

I'm trying to get a variable geom type using ggplot2 in a Shiny plot.

if (type == "column") {
    geom <- geom_col() 
} else {
    geom <- geom_line() + geom_point()
}

qplot(1:10, 1:10) + geom

This works if we remove the "geom_point" however combining them doesn't return the expression but is rather evaluated separately (which is impossible: cannot add ggproto objects together). Is there some sort of work around that doesn't require storing the plot and then adding the geom?

I can't reproduce it, but just a wild guess what happens if you wrap the else with a list as follows: geom <- list(geom_line() + geom_point())? — deepseefan
No good sorry: still tries to evaluate geom_col() + geom_point() inside the list function which is still impossible. — Daniel V

Maurits Evers Maurits Evers · Accepted Answer · 2019-10-31T04:44:10

It does work if you store the geoms in a list

my_geom <- function(type)
    if (type == "column") list(geom_col()) else list(geom_line(), geom_point())

qplot(1:10, 1:10) + my_geom("column")

qplot(1:10, 1:10) + my_geom("other")

Stored/flexible geom

1 Answers