Use a variable within a plotmath expression
Use bquote(). Here is an example with dummy data:
set.seed(1)DF <- data.frame(A = rnorm(100), B = rnorm(100))mod <- lm(B ~ A, data = DF)R2Val<-signif(summary(mod)$r.squared[1], 2)The parts of the expression wrapped in .() get evaluated in the environment, i.e. the value of R2Val is substituted.
plot(B ~ A, data = DF)text(1.5, 2, labels = bquote(R^2 == .(R2Val)), adj = 0, cex = 0.85)Another potential solution is substitute, which works similarly:
plot(B ~ A, data = DF)text(1.5, 2, labels = substitute(R^2 == A, list(A = R2Val)), adj = 0, cex = 0.85)