plot continuous and dummy w interaction term

ols_w_interaction_gg

compute_panel_ols_ind <- function(data, scales) {
  
  model <- lm(y ~ x*indicator,
              data = data)
  
  data.frame(x = data$x,
             y = model$fitted.values,
             indicator = data$indicator)
  
}







StatLminteraction <- ggplot2::ggproto("StatLminteraction",
                                    ggplot2::Stat,
                                    compute_panel = compute_panel_ols_ind,
                                    required_aes = c("x", "y", "indicator"),
                                    default_aes = aes(group = after_stat(indicator))
)

geom_lm_interaction <- function(mapping = NULL, data = NULL,
                              position = "identity", na.rm = FALSE,
                              show.legend = NA,
                              inherit.aes = TRUE, ...) {
  ggplot2::layer(
    stat = StatLminteraction, # proto object from Step 2
    geom = ggplot2::GeomLine, # inherit other behavior
    data = data,
    mapping = mapping,
    position = position,
    show.legend = show.legend,
    inherit.aes = inherit.aes,
    params = list(na.rm = na.rm, ...)
  )
}


geom_lm_interaction_fitted <- function(mapping = NULL, data = NULL,
                                     position = "identity", na.rm = FALSE,
                                     show.legend = NA,
                                     inherit.aes = TRUE, ...) {
  ggplot2::layer(
    stat = StatLminteraction, # proto object from Step 2
    geom = ggplot2::GeomPoint, # inherit other behavior
    data = data,
    mapping = mapping,
    position = position,
    show.legend = show.legend,
    inherit.aes = inherit.aes,
    params = list(na.rm = na.rm, ...)
  )
}




compute_panel_ols_int_label <- function(data, scales) {
  
  model <- lm(y ~ x*indicator,
              data = data)
  
  data.frame(names = model[[1]] %>% names(),
             coeff = model[[1]]) %>% 
    tibble() %>% 
    slice(-1, -2) %>% 
    mutate(equation = paste0(coeff %>% good_digits(), "*", names)) %>% 
    pull(equation) %>% 
    paste(collapse = " + ") ->
    dummies
  
  
  data.frame(x = mean(data$x),
             y = mean(data$y),
             label = paste0("y = ",
                            model$coefficients[2] %>% good_digits(), 
                            "x + ",
                            dummies,
                            " + ",
                            model$coefficients[1] %>% good_digits() %>% str_wrap(50)
                            
             ))
  
}



StatOlsintformula <- ggplot2::ggproto("StatOlsintformula",
                                      ggplot2::Stat,
                                      compute_panel = compute_panel_ols_int_label,
                                      required_aes = c("x", "y", "indicator")
)


geom_lm_interaction_formula <- function(mapping = NULL, data = NULL,
                                      position = "identity", na.rm = FALSE, show.legend = NA,
                                      inherit.aes = TRUE, ...) {
  ggplot2::layer(
    stat = StatOlsintformula, geom = ggplot2::GeomLabel, data = data, mapping = mapping,
    position = position, show.legend = show.legend, inherit.aes = inherit.aes,
    params = list(na.rm = na.rm, ...)
  )
}