Get equation text from a R lm (Linear Model) object for use as text in graph

get_lm_equation.R

# Get equation text from LM
# Format: y = a + b.x, R^2 = r^2
equation_text = function(x, round_dig = 2) {
  lm_coef <- list(a = as.character(round(coef(x)[1], digits = round_dig)),
                  b = as.character(round(coef(x)[2], digits = round_dig)),
                  r2 = round(summary(x)$r.squared, digits = round_dig));
  lm_eq <- substitute(italic(y) == a + b %.% italic(x)*","~~italic(R)^2~"="~r2,lm_coef)
  as.character(as.expression(lm_eq));                 
}