How to use mapply on stat_poly_eq (i.e. equation and R-squared values) in ggplot2 R?-CodePudding

I am trying to add the R-squared equations, each with a different formula. I tried the mapply function modelling on a p

CodePudding user response：

The issue with your code was a wrong closing paranthesis, i.e. you included my.formula and c("A","M","T") as arguments of stat_poly_eq. That's why no labels were plotted as you looped over nothing.

Concerning your second question. TBMK you can't have a line break in a math expression. One approach to deal with that would be to add the equation and the R^2 via two separate stat_poly_eq layers.

Additionally I simplified your code a bit. It's not necessary to have multiple mapplys. One is sufficient. You could return multiple layers by wrapping them inside a list.

library(ggplot2)
library(ggpmisc)

ggplot(df, aes(x = x, y = val.test))  
  geom_point()  
  mapply(function(x, z) {
    data <- subset(df, var.test == z)
    list(
      geom_smooth(
        method = "glm", data = data, formula = x,
        method.args = list(family = "poisson"), color = "black"
      ),
      stat_poly_eq(formula = x, aes(label = ..eq.label..), 
                   parse = TRUE, size = 2.5, col = "black", data = data, vjust = -0.1),
      stat_poly_eq(formula = x, aes(label = ..rr.label..), 
                   parse = TRUE, size = 2.5, col = "black", data = data, vjust = 1.1)
    )
  }, my.formula, c("A", "M", "T"))  
  facet_grid(. ~ var.test)