Barcharts: grouping bars using facet

I want to group these bars by the variable "env".

ggplot(dat, aes(x = Sample, fill = phylum, y = Abundance))      
  geom_bar(position="fill", stat = "identity")   theme_bw()   
  facet_wrap( ~ env)  
  theme(axis.text.x = element_text(angle = 90, size = 13, colour = "black", vjust = 0.5, hjust = 1), axis.title.x = element_text(size = 15),
        axis.text.y = element_text(size = 13, vjust = 0.5, hjust = 1), axis.title.y = element_text(size = 15), legend.title = element_text(size = 15),  
        legend.text = element_text(size = 15, colour = "black"))   
  ggtitle("Minion samples: Proteobacteria Phyla")   scale_y_continuous(labels = percent_format(), limits=c(0,1))  
  scale_fill_manual(values = c("Acidobacteria"="#3288bd", 
                               "Actinobacteria" = "#99d594",
                               "Candidatus Rokubacteria" = "#74c476",
                               "Chloroflexi"= "#e6f598",
                               "Planctomycetes"="#fee08b",
                               "Proteobacteria" = "#fc8d59",
                               "Verrucomicrobia" = "#a50f15",
                               "Taxa less than 1%" = "#d53e4f"))

I get this:

I would like to have an unique x-axis and get rid of these empty spaces. Is there an other option beside facet_wrap?

Thanks

CodePudding user response：

As per the comments, indeed using facet_wrap(~env, scales = "free, nrow =1) will solve your issue.

Moreover, you might want to have an equal width for the histograms, in this case you can use facet_grid and the space argument to have something like this:

ggplot(dat, aes(x = Sample, fill = phylum, y = Abundance))      
  geom_bar(position="fill", stat = "identity")   theme_bw()  
  facet_grid(. ~ env, scales = "free", space = "free") 
  theme(axis.text.x = element_text(angle = 90, size = 13, colour = "black", vjust = 0.5, hjust = 1), axis.title.x = element_text(size = 15),
        axis.text.y = element_text(size = 13, vjust = 0.5, hjust = 1), axis.title.y = element_text(size = 15), legend.title = element_text(size = 15),  
        legend.text = element_text(size = 15, colour = "black"))   
  ggtitle("Minion samples: Proteobacteria Phyla")   scale_y_continuous(labels = percent_format(), limits=c(0,1))  
  scale_fill_manual(values = c("Acidobacteria"="#3288bd", 
                               "Actinobacteria" = "#99d594",
                               "Candidatus Rokubacteria" = "#74c476",
                               "Chloroflexi"= "#e6f598",
                               "Planctomycetes"="#fee08b",
                               "Proteobacteria" = "#fc8d59",
                               "Verrucomicrobia" = "#a50f15",
                               "Taxa less than 1%" = "#d53e4f"))

Whereas, facet_wrap(~ env, scales = "free", nrow = 1) results in unequal width distribution when free on one row:

ggplot(dat, aes(x = Sample, fill = phylum, y = Abundance))      
  geom_bar(position="fill", stat = "identity")   theme_bw()  
  facet_wrap(~ env, scales = "free", nrow = 1) 
  theme(axis.text.x = element_text(angle = 90, size = 13, colour = "black", vjust = 0.5, hjust = 1), axis.title.x = element_text(size = 15),
        axis.text.y = element_text(size = 13, vjust = 0.5, hjust = 1), axis.title.y = element_text(size = 15), legend.title = element_text(size = 15),  
        legend.text = element_text(size = 15, colour = "black"))   
  ggtitle("Minion samples: Proteobacteria Phyla")   scale_y_continuous(labels = percent_format(), limits=c(0,1))  
  scale_fill_manual(values = c("Acidobacteria"="#3288bd", 
                               "Actinobacteria" = "#99d594",
                               "Candidatus Rokubacteria" = "#74c476",
                               "Chloroflexi"= "#e6f598",
                               "Planctomycetes"="#fee08b",
                               "Proteobacteria" = "#fc8d59",
                               "Verrucomicrobia" = "#a50f15",
                               "Taxa less than 1%" = "#d53e4f"))

Data

library(scales)
library(ggplot2)

set.seed(18)
dat = data.frame(
  env = factor(rep(sample(c("Dry", "Fossil", "Wet", "Soil"), size = 25, prob = c(3,2,18,2), replace = T), each=8), levels =c("Dry", "Fossil", "Wet", "Soil")),
  Sample = rep(paste0("Sample_",letters[1:25]), each=8),
  phylum = rep(c("Acidobacteria", "Actinobacteria","Candidatus Rokubacteria","Chloroflexi","Planctomycetes", "Proteobacteria", "Verrucomicrobia","Taxa less than 1%"),times = 25),
  Abundance = runif(200,0,1))