Simplest way to do grouped barplot

Question

I have the following dataframe:

 Catergory        Reason Species
1   Decline       Genuine      24
2  Improved       Genuine      16
3  Improved Misclassified      85
4   Decline Misclassified      41
5   Decline     Taxonomic       2
6  Improved     Taxonomic       7
7   Decline       Unclear      41
8  Improved       Unclear     117

I'm trying to make a grouped bar chart, species as height and then 2 colours for catergory.

here is my code:

Reasonstats<-read.csv("bothstats.csv")
Reasonstats2<-as.matrix(Reasonstats[,3])


barplot((Reasonstats2),beside=T,col=c("darkblue","red"),ylab="number of 
species",names.arg=Reasonstats$Reason, cex.names=0.8,las=2,space=c(0,100)
,ylim=c(0,120))
box(bty="l")

Now what I want, is to not have to label the two bars twice and to group them apart, I've tried changing the space value to all sorts of things and it doesn't seem to move the bars apart. Can anyone tell me what I'm doing wrong?

score 54 · Answer 1 · answered Jul 18 '13 at 14:46

54

with ggplot2:

library(ggplot2)
Animals <- read.table(
  header=TRUE, text='Category        Reason Species
1   Decline       Genuine      24
2  Improved       Genuine      16
3  Improved Misclassified      85
4   Decline Misclassified      41
5   Decline     Taxonomic       2
6  Improved     Taxonomic       7
7   Decline       Unclear      41
8  Improved       Unclear     117')

ggplot(Animals, aes(factor(Reason), Species, fill = Category)) + 
  geom_bar(stat="identity", position = "dodge") + 
  scale_fill_brewer(palette = "Set1")

Bar Chart

answered Jul 18 '13 at 14:46

Jack Ryan

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Very useful, Thank you! – ganeshran Sep 26 '16 at 09:28
1

@Jack Ryan Shoul it be `ggplot(Animals, aes(factor(Reason), Species` or `ggplot(Animals, aes(factor(Reason), as.factor(Species)` ? Because in my case I hade the data like same format but it made a stack bar instead of a group bar. – RKR Apr 27 '17 at 06:27
As RKR pointed out, ggplot expects factors while plotting a grouped bar chart. I also had a similar data but I wasn't reading the columns as factors due to other requirements and I wasn't able to plot a grouped bar till I identified this requirement. – iMajetyHK Sep 08 '18 at 04:46

score 31 · Answer 2 · edited Jul 18 '13 at 12:11

31

Not a barplot solution but using lattice and barchart:

library(lattice)
barchart(Species~Reason,data=Reasonstats,groups=Catergory, 
         scales=list(x=list(rot=90,cex=0.8)))

enter image description here

edited Jul 18 '13 at 12:11

Jilber Urbina

58,147
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answered Jul 18 '13 at 10:54

agstudy

119,832
17
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261

1

what about legend for colours here? – maciek Oct 07 '16 at 08:31
1

@maciek You can use `auto.key = T` within `barchart` function to have the legend. – UseR10085 Jul 23 '20 at 09:38

gung - Reinstate Monica · Answer 3 · 2019-08-23T17:12:38.843

There are several ways to do plots in R; lattice is one of them, and always a reasonable solution, +1 to @agstudy. If you want to do this in base graphics, you could try the following:

Reasonstats <- read.table(text="Category         Reason  Species
                                 Decline        Genuine       24
                                Improved        Genuine       16
                                Improved  Misclassified       85
                                 Decline  Misclassified       41
                                 Decline      Taxonomic        2
                                Improved      Taxonomic        7
                                 Decline        Unclear       41
                                Improved        Unclear      117", header=T)

ReasonstatsDec <- Reasonstats[which(Reasonstats$Category=="Decline"),]
ReasonstatsImp <- Reasonstats[which(Reasonstats$Category=="Improved"),]
Reasonstats3   <- cbind(ReasonstatsImp[,3], ReasonstatsDec[,3])
colnames(Reasonstats3) <- c("Improved", "Decline")
rownames(Reasonstats3) <- ReasonstatsImp$Reason

windows()
  barplot(t(Reasonstats3), beside=TRUE, ylab="number of species", 
          cex.names=0.8, las=2, ylim=c(0,120), col=c("darkblue","red"))
  box(bty="l")

enter image description here

Here's what I did: I created a matrix with two columns (because your data were in columns) where the columns were the species counts for Decline and for Improved. Then I made those categories the column names. I also made the Reasons the row names. The barplot() function can operate over this matrix, but wants the data in rows rather than columns, so I fed it a transposed version of the matrix. Lastly, I deleted some of your arguments to your barplot() function call that were no longer needed. In other words, the problem was that your data weren't set up the way barplot() wants for your intended output.

Thanks. One advantage of using basic graphis is that you can assambly several basic plots using par() or layout(). — giordano, Dec 18 '16 at 16:30

score 17 · Answer 4 · answered Jul 18 '13 at 13:19

17

I wrote a function wrapper called bar() for barplot() to do what you are trying to do here, since I need to do similar things frequently. The Github link to the function is here. After copying and pasting it into R, you do

bar(dv = Species, 
    factors = c(Category, Reason), 
    dataframe = Reasonstats, 
    errbar = FALSE, 
    ylim=c(0, 140))  #I increased the upper y-limit to accommodate the legend.

The one convenience is that it will put a legend on the plot using the names of the levels in your categorical variable (e.g., "Decline" and "Improved"). If each of your levels has multiple observations, it can also plot the error bars (which does not apply here, hence errbar=FALSE

enter image description here

answered Jul 18 '13 at 13:19

Alex

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Where do I define the column to be used for the errorbars when using the wrapper? Thanks – heysamhey Jul 05 '17 at 10:52
I'm wondering, is there a way to stack this histogram? I want to create a three-panel figure, the first two with regular grouped bar plots as this function allows, and then the third one with each bar separated into two parts. 1/2 – Ella Bowles Jul 30 '19 at 22:28
2/2 -- IF I have bar(dv = numoutspc1, factors = c(Sex, Population), dataframe = WALL, errbar = FALSE, col=c("red","purple","blue"), ylab=c("Number of outliers associated with each PCaxis"), ylim=c(0, 240)) ###but I want numoutsPC2 in each bar as well. – Ella Bowles Jul 30 '19 at 22:28

Simplest way to do grouped barplot

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