Removing underscores from ggplot2 boxplot

Question

I would like to remove an underscore out of my ggplot2 boxplot (the head of fill "fungicide_treatment".

I already tried to change the column head in my excel data file, and I tried already the function labels = ~ gsub("_", " ", .x) in my scale_fill section of my code. The underscore did not go away with these two trials. Maybe I placed the gsub function in the wrong position in my code?

Here my boxplot: Here my gglpot2 code in R:

ggplot(df3, aes(x = Drechslera_treatment, y = Abundance, fill=Fungicide_treatment)) +
  geom_boxplot(lwd=0.1)+ xlab("Drechslera treatment") + ylab("Unidentified fungi abundance / plant")+
  scale_fill_manual(values=c("#90EE90", "#228822"))+ theme_linedraw()+theme_bw()+
  theme(axis.text.x = element_text(size=07), axis.text.y = element_text(size=14))+ 
  theme(axis.title.x = element_text(size=14, face="bold"), axis.title.y = element_text(size=14, face="bold"))+
  facet_grid(, vars(Cultivar))

I would be very thankful for some hints to solve that. Wish you all a good night! Greetings from Munich. Stephan Grassl, Terrestrial Ecology, Munich

Answer 1

One possible solution would be to rename your column with code like this colnames(data)[colnames(data) == "Old_Name"] <- "New_Name" and then use back-ticks when referencing it in your ggplot

So for your data it would be:

colnames(df3)[colnames(df3) == "Fungicide_treatment"] <- "Fungicide treatment"


ggplot(df3, aes(x = Drechslera_treatment, y = Abundance, fill=`Fungicide treatment`)) + 
    geom_boxplot(lwd=0.1)+ 
    xlab("Drechslera treatment") + 
    ylab("Unidentified fungi abundance / plant")+ 
    scale_fill_manual(values=c("#90EE90", "#228822"))+ 
    theme_linedraw()+theme_bw()+ 
    theme(axis.text.x = element_text(size=07), axis.text.y = element_text(size=14), axis.title.x = element_text(size=14, face="bold"), axis.title.y = element_text(size=14, face="bold"))+ 
    facet_grid(, vars(Cultivar))

Alternatively, as suggested in the comment by mikeck you can change the legend title using the scale_fill_manual() function like so:

ggplot(df3, aes(x = Drechslera_treatment, y = Abundance, fill=Fungicide_treatment)) + 
    geom_boxplot(lwd=0.1)+ 
    xlab("Drechslera treatment") + 
    ylab("Unidentified fungi abundance / plant")+ 
    scale_fill_manual("Fungicide treatment", values=c("#90EE90", "#228822"))+ #simply add your legend title here
    theme_linedraw()+theme_bw()+ 
    theme(axis.text.x = element_text(size=07), axis.text.y = element_text(size=14), axis.title.x = element_text(size=14, face="bold"), axis.title.y = element_text(size=14, face="bold"))+ 
    facet_grid(, vars(Cultivar))