plot_model_pred.R

plot_model_pred <-
  function(data,
           key = NULL,
           plot_units = TRUE,
           scales_free = TRUE,
           x_var_name = NULL,
           y_var_name = NULL,
           line = TRUE,
           col_by_price = FALSE,
           plot_80 = FALSE,
           plot_50 = TRUE,
           mid = 11,
           plot_current_price = FALSE) {
    if (is.null(key)) {
      p <- ggplot(data,
                  aes(x = eval(parse(text = x_var_name)),
                      y = eval(parse(text = y_var_name))),
                  group = factor(prod_key))
      if (scales_free)
        p <- p + facet_wrap(~ prod_key, scales = "free")
      else
        p <- p + facet_wrap(~ prod_key)
    }
    else
      p <-
        ggplot(filter(data, prod_key == key),
               aes(x = eval(parse(text = x_var_name)),
                   y = eval(parse(text = y_var_name))))
    
    if (col_by_price)
      p <- p + geom_point(aes(color = price), size = 2) +
        scale_colour_gradient2(
          low = "green",
          high = "red",
          mid = "yellow",
          midpoint = mid
        )
    else {
      p <- p + geom_point(size = 0.5, color = "red")
      if (x_var_name == "price")
        p <-
          p + scale_x_continuous(breaks = seq(min(unique(data$price)),
                                              max(unique(data$price)), by = 2))
    }
    
    if (plot_80)
      if (plot_units)
        p <-
          p + geom_linerange(aes(ymin = units_q10, ymax = units_q90),
                             color = "blue",
                             size = 0.15)
      else
        # plotting revenue
        p <- p + geom_linerange(aes(ymin = rev_q10, ymax = rev_q90),
                                color = "blue",
                                size = 0.15)
      
      if (plot_50)
        if (plot_units)
          p <- p + geom_linerange(
            aes(ymin = units_q25, ymax = units_q75),
            alpha = 1 / 5,
            color = "blue",
            size = 2
          )
        else
          # plotting revenue
          p <- p + geom_linerange(
            aes(ymin = rev_q25, ymax = rev_q75),
            alpha = 1 / 5,
            color = "blue",
            size = 2
          )
        
        p <-
          p + xlab(x_var_name) + ylab(y_var_name) + theme_minimal() +
          theme(axis.text.x = element_text(angle = 90))
        
        if (length(unique(data$prod_key)) > 50)
          p <- p + theme(text = element_text(size = 10))
        
        if (plot_current_price)
          p <- p + geom_vline(aes(xintercept = current_price),
                              colour = "blue",
                              size = 0.1)
        if (line)
          p <- p + geom_line(size = 0.1)
        
        return(p)
}