gridExtra::marrangeGrob

qPCR_multiplot.R

library("ggplot2")
library("dplyr", warn.conflicts = FALSE)
library("gridExtra")

plot_id <- function(df, df2, type) {
  df %>%
    filter(`2^-ddCt` > 2, id == type) %>%
    mutate(analysis = "HKgenorm:arith") %>%
    ggplot(aes(x = ID, y = log2(`2^-ddCt`), colour = analysis))+
    geom_pointrange(aes(ymin = log2(`2^-ddCt.min`), ymax = log2(`2^-ddCt.max`)),
                    alpha = 0.7)+
    geom_point(data = filter(df2, id == type, `2^-ddCt` > 2),  alpha = 0.7)+
    coord_flip()+
    scale_color_manual(name = type, values = c("purple", "red"))+
    theme_bw(14)+
    theme(axis.text.y = element_text(size = 5))+
    xlab(NULL)
}

# plots on multiple pages
Plots <- lapply(unique(res$id), function(x) plot_id(res, old_res, x))
myPlots <- do.call(marrangeGrob, list(grobs=Plots, nrow = 1, ncol = 1))
ggsave("global_genorm.pdf", myPlots, height = 11.69, width = 8.27)