scale_x_discrete 轴标签不正确

Question

I am trying to plot a ggplot boxplot using facet_wrap to show two sites. My x axis has three possible treatments, control, bagged, or scattered. In order to remove an empty column in the facet_wrap , I have used facet_wrap(~site, scales = "free_x") , as each site contains a control and either bagged or scattered. I also want to change my axis labels from 'A_Control' to 'Control' etc, so have used scale_x_discrete(labels = c('Control','Bagged','Scattered')) . However, my problem is when I use the below code to plot it, it removes the label for scattered and replaces it with bagged for site B, and I'm struggling to work out where the problem is. I have included the incorrect plot at the bottom.

  geom_boxplot()+
  stat_summary(fun.y = mean, geom="point", color="red")+
  scale_x_discrete(labels = c('Control','Bagged','Scattered'))+
  facet_wrap(~site, scales = "free_x")

My data:

  salmon_biomass = c(0.263678451,0.721658206,
                     0.214856902,0.267343486,0.250631313,0.105008418,2.645833333,
                     1.702020202),
            site = as.factor(c("Site A",
                               "Site A","Site A","Site A","Site B","Site B",
                               "Site B","Site B")),
         section = as.factor(c("A", "A", "B", "B", "A", "A", "B", "B")),
       treatment = as.factor(c("A_Control",
                               "B_Bagged","A_Control","B_Bagged","A_Control",
                               "C_Scattered","A_Control","C_Scattered"))```

Answer 1

You can pass a named vector for the labels in scale_x_discrete :

  ggplot(df, aes(treatment, salmon_biomass)) +
    geom_boxplot()+
    stat_summary(fun.y = mean, geom="point", color="red")+
    scale_x_discrete(labels = c(B_Bagged = "Bagged", 
                                A_Control = 'Control',
                                C_Scattered = 'Scattered')) +
    facet_wrap(~site, scales = "free_x")