ggplot2条形图的宽度相同

Question

I want to draw a bar plot using ggplot2 so that the bars have the same width. I have the following data-set.

     sexratio=c("0%male","0%male","0%male","0%male","25%male","25%male","50%male","50%male" ,"75%male","75%male","100%male","100%male","100%male", "100%male") 
     Trainsize=c("Ts130","Ts260","Ts520","Ts1040","Ts130", "Ts1040","Ts130", "Ts1040", "Ts130", "Ts1040","Ts130", "Ts260", "Ts520", "Ts1040") 
     Dm1=c(354.7015, 362.6982, 369.8013, 380.7233, 363.2208, 415.8980, 367.2899, 413.7292, 365.1060, 409.1913, 366.9871, 377.3490, 389.0739, 400.5590) 
     mydata=data.frame(Trainsize,sexratio,Dm1)

     #Reorder the fators
     mydata$sexratio<−factor(mydata$sexratio,levels(mydata$sexratio)[c(2:4,1)])

     mydata$Trainsize<- factor(mydata$Trainsize,levels(mydata$Trainsize)[c(2:4,1)]) 

I used the following code to draw the plot, but note that the width of the bars for Ts260 and Ts520 are larger.

     p2<- ggplot(mydata, aes(x=Trainsize, y=Dm1, fill=sexratio)) +geom_bar(stat="identity", color="black",position=position_dodge()) +
       geom_errorbar(aes(ymin=Dm1-10, ymax=Dm1+10), width=.2,position=position_dodge(.9))  

So I include NA for missing values for Ts260 and Ts520, and redraw the plot.

    require(utils) 
    dat<-expand.grid( sexratio= c("25%male","50%male","75%male"), Trainsize= c("Ts260","Ts520"))

    dat$Dm1<- NA 
    mydata<- rbind(mydata,dat)

    p2<- ggplot(mydata, aes(x=Trainsize, y=Dm1, fill=sexratio)) +

      geom_bar(stat="identity", color="black", 
               position=position_dodge()) +
      geom_errorbar(aes(ymin=Dm1-10, ymax=Dm1+10), width=.2,
                    position=position_dodge(.9))

The question now is how do I reduce the space between Ts260, Ts520 for 0%male and 100%male.

Or how do I draw vertical lines between the levels of the factor TS; that is four vertical lines at Ts130, Ts260, Ts520, Ts1040.

Answer 1

If I understand correctly, you want the same width for all bars, but also you want the space between the bars to be the same.

First, there appears to be problem with your code: you drop one of the factor levels for sexratio . Here, I arrange the levels for sexratio in order from 0% through to 100%.

Second, let me show you the effect of using facet.grid using your second version of mydata ; here named mydata2 . The strip text is moved to the bottom using switch = "x" .

library(ggplot2)

# Some data
sexratio=c("0%male","0%male","0%male","0%male","25%male","25%male","50%male","50%male" ,"75%male","75%male","100%male","100%male","100%male", "100%male") 
     Trainsize=c("Ts130","Ts260","Ts520","Ts1040","Ts130", "Ts1040","Ts130", "Ts1040", "Ts130", "Ts1040","Ts130", "Ts260", "Ts520", "Ts1040") 
     Dm1=c(354.7015, 362.6982, 369.8013, 380.7233, 363.2208, 415.8980, 367.2899, 413.7292, 365.1060, 409.1913, 366.9871, 377.3490, 389.0739, 400.5590) 

mydata=data.frame(Trainsize,sexratio,Dm1)

mydata$sexratio <− factor(mydata$sexratio, levels(mydata$sexratio)[c(2,5,4,3,1)])
mydata$Trainsize <- factor(mydata$Trainsize,levels(mydata$Trainsize)[c(2:4,1)]) 

# Add NAs where sexratio categories are missing
dat <- expand.grid(sexratio = c("25%male", "50%male", "75%male"), Trainsize = c("Ts260", "Ts520"))

dat$Dm1 <- NA 
mydata2 <- rbind(mydata, dat)

# The plot
ggplot(mydata2, aes(x = Trainsize, y = Dm1, fill = sexratio)) +
   geom_bar(stat = "identity", color = "black", position = position_dodge(width = .85)) +
   geom_errorbar(aes(ymin = Dm1 - 10, ymax = Dm1 + 10), width = .2, 
      position = position_dodge(width = .85)) +
   facet_grid(. ~ Trainsize, scales = "free_x", switch = "x") +
      theme(axis.text.x = element_blank(), 
            strip.background = element_rect(fill = NA))

In my opinion, this is a better chart than the one that follows becaus it draws the reader's attention to the fact that there are gaps in the data.

But if you insist on there being no spacing between the bars, then something like this gets you close. It uses your first version of mydata ; it uses facet_grid with both scales and space set to "free_x" ; moves the strip text to the bottom ( switch = "x" ); plus some tidying up.

ggplot(mydata, aes(x = factor(1:dim(mydata)[1]), y = Dm1, fill = sexratio)) +
      geom_bar(stat = "identity", color = "black", width = 1) +
      geom_errorbar(aes(ymin = Dm1 - 10, ymax = Dm1+10), width = .2) +
      facet_grid(. ~ Trainsize, scales = "free_x", space = "free_x", switch = "x") +
      scale_x_discrete("Trainsize", expand = c(0, .75)) +
      theme(axis.text.x = element_blank(), 
            strip.background = element_rect(fill = NA),
            axis.ticks.x = element_blank())