Controlling the labels on the primary and secondary axis with facet

The following code produces a single plot:

data <- tibble(model = rep(c("model 0", "model I", "model II", "model III", "model IV"),3),
                year = c(rep('2005-2009', 5), rep('2010-2014',5), rep('2015-2017',5)),
                value = c(0.0, 10.4, 30.7, 26.7, 32.2, 0.0, 9.9, 31.0, 26.5, 32.6, 0.0, 19.1, 29.6, 25.6, 25.7),
                unknown = c(rep(30,5), rep(40,5), rep(27,5)),
                region = 'Asia')

# Numeric year
data$year_num <- as.numeric(factor(data$year))
# Labels for primary scale
labels <- levels(factor(data$year))
# Labels for secondary scale
dup_labels <- distinct(data, year, unknown) %>% tibble::deframe()

p1 <- ggplot(data, aes(fill=model, x=value, y = year_num))   
  geom_bar(stat='identity', position = position_fill(reverse = TRUE), orientation = "y")  
  scale_fill_grey(start=0.8, end=0.2)  
  theme_bw()  
  ggtitle('Model')  
  xlab('')   ylab('')  
  theme(legend.position="bottom",
        plot.title = element_text(hjust = 0.5),
        legend.title=element_blank(),
        text = element_text(family = "serif")
  )  
  scale_x_continuous(labels = percent_format(scale = 100))  
  scale_y_continuous(breaks = seq_along(labels), labels = labels, sec.axis = dup_axis(labels = dup_labels))

p1

Next, I would like to produce several plots with facet_wrap but I have a challenge controlling the labels. I am not quite sure how to iterate the labels for the corresponding plot.

Eg., if I want to plot the following data with facet_wrap(~region, dir = 'v', nrow = 2):

data1 <- tibble(model = rep(c("model 0", "model I", "model II", "model III", "model IV"),3),
                year = c(rep('2005-2009', 5), rep('2010-2014',5), rep('2015-2017',5)),
                value = c(0.0, 10.4, 30.7, 26.7, 32.2, 0.0, 9.9, 31.0, 26.5, 32.6, 0.0, 19.1, 29.6, 25.6, 25.7),
                unknown = c(rep(30,5), rep(40,5), rep(27,5)),
                region = 'Asia')

data2 <- tibble(model = rep(c("model 0", "model I", "model II", "model III", "model IV"),3),
                year = c(rep('2005-2009', 5), rep('2010-2014',5), rep('2015-2017',5)),
                value = c(0.4, 15.0, 25.6, 20.6, 38.3, 1.1, 15, 13, 14.6, 56.9, 0.8, 19.8, 22, 18.8,38.1),
                unknown = c(rep(28,5), rep(35,5), rep(17,5)),
                region = 'Europe')

data <- rbind(data1, data2)

I reckon that I need to have some sort of iteration but I can't really figure it out for this problem.

CodePudding user response：

One option would be the ggh4x package which allows to set a scale for each facet via ggh4x::facetted_pos_scales.

To this end, make e.g. a list of labels for your dup_axis then add a scale with the respective dup_labels to each facet via ggh4x::facetted_pos_scales:

library(ggplot2)
library(ggh4x)
library(scales)
library(dplyr)

# Numeric year
data$year_num <- as.numeric(factor(data$year))
# Labels for primary scale
labels <- levels(factor(data$year))
# Make a list of labels for secondary scale by region
dup_labels <- data %>% 
  split(.$region) %>% 
  lapply(function(x) distinct(x, year, unknown) %>% tibble::deframe())

p <- ggplot(data, aes(fill=model, x=value, y = year_num))   
  geom_bar(stat='identity', position = position_fill(reverse = TRUE), orientation = "y")  
  scale_fill_grey(start=0.8, end=0.2)  
  theme_bw()  
  ggtitle('Model')  
  xlab('')   ylab('')  
  theme(legend.position="bottom",
        plot.title = element_text(hjust = 0.5),
        legend.title=element_blank(),
        text = element_text(family = "serif")
  )  
  scale_x_continuous(labels = percent_format(scale = 100))  
  facet_wrap(~region, nrow = 2, scales = "free_y")

p  
  facetted_pos_scales(
    y = list(
      scale_y_continuous(breaks = seq_along(labels), labels = labels, sec.axis = dup_axis(labels = dup_labels[["Asia"]])), 
      scale_y_continuous(breaks = seq_along(labels), labels = labels, sec.axis = dup_axis(labels = dup_labels[["Europe"]])))
  )

Or instead of duplicating the code to add the scale for each region you could make use of e.g. lapply:

p   facetted_pos_scales(y = lapply(dup_labels, function(x) scale_y_continuous(breaks = seq_along(labels), labels = labels, sec.axis = dup_axis(labels = x))))

CodePudding user response：

Facet-wrap will automatically label based on the values for the facet specified. In your case you are wrapping on the facet 'region,' so your plots will be labeled "Asia" and "Europe." If you want another label, this is generally accomplished with labeller as an argument to facet_wrap.