R help - Mar 2015 - Order Bars in ggplot2 bar graph

Dear experts,
I am trying to make a bar graph using ggplot2. I would like to define the order
of my bars independently of alphabetical or numerical order.
How can I do that.
Here a simplified example of my code and comments(#) describing my problem:


#Code start


library(ggplot2)

bar<-ggplot(data,aes(Leaf,Av_Glands_cor,fill=Damage))



# The column "Leaf"  contains the variable C_1, C_2 and C_Cot. R
always plots the bars in the following orders : C_1 (closest to the y-axis),
C_2, C_Cot

# How do I have to modify my code that the order of the bars is: C_Cot, C_2,
C_1?



bar+stat_summary(fun.y=mean,geom="bar",position="dodge",colour="black")+

  theme_bw()+

  theme(text = element_text(size=15),

        axis.text.x = element_text(angle=90, vjust=1))+

stat_summary(fun.data=mean_cl_normal,geom="errorbar",position=position_dodge(width=0.9),width=0.4,colour="gray65")+

labs(x="Leaf",y="Average nr. glands corrected for leaf
sz.",fill="Damage")+

  scale_fill_manual(values=c("gray95", "gray75",
"gray45", "black"))

#Code end


Thank you very much,
Michael Eisenring

Eisenring Michael, Msc.
PhD Student

Federal Department of Economic Affairs, Education and Research
EAER
Institute of Sustainability Sciences ISS
Biosafety

Reckenholzstrasse 191, CH-8046 Z?rich
Tel. +41 44 37 77181
Fax +41 44 37 77201
michael.eisenring at agroscope.admin.ch<mailto:michael.eisenring at
agroscope.admin.ch>
www.agroscope.ch<http://www.agroscope.ch/>


	[[alternative HTML version deleted]]

You need to set the levels of the factor in the required order.

data$Leaf <- factor(data$Leaf, levels = c("C_Cot", "C_2",
"C_1"))

ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to say
what the experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey

2015-03-19 10:06 GMT+01:00 <michael.eisenring at agroscope.admin.ch>:
> Dear experts,
> I am trying to make a bar graph using ggplot2. I would like to define the
> order of my bars independently of alphabetical or numerical order.
> How can I do that.
> Here a simplified example of my code and comments(#) describing my problem:
>
>
> #Code start
>
>
> library(ggplot2)
>
> bar<-ggplot(data,aes(Leaf,Av_Glands_cor,fill=Damage))
>
>
>
> # The column "Leaf"  contains the variable C_1, C_2 and C_Cot. R
always
> plots the bars in the following orders : C_1 (closest to the y-axis), C_2,
> C_Cot
>
> # How do I have to modify my code that the order of the bars is: C_Cot,
> C_2, C_1?
>
>
>
>
bar+stat_summary(fun.y=mean,geom="bar",position="dodge",colour="black")+
>
>   theme_bw()+
>
>   theme(text = element_text(size=15),
>
>         axis.text.x = element_text(angle=90, vjust=1))+
>
>
>
stat_summary(fun.data=mean_cl_normal,geom="errorbar",position=position_dodge(width=0.9),width=0.4,colour="gray65")+
>
> labs(x="Leaf",y="Average nr. glands corrected for leaf
sz.",fill="Damage")+
>
>   scale_fill_manual(values=c("gray95", "gray75",
"gray45", "black"))
>
> #Code end
>
>
> Thank you very much,
> Michael Eisenring
>
> Eisenring Michael, Msc.
> PhD Student
>
> Federal Department of Economic Affairs, Education and Research
> EAER
> Institute of Sustainability Sciences ISS
> Biosafety
>
> Reckenholzstrasse 191, CH-8046 Z?rich
> Tel. +41 44 37 77181
> Fax +41 44 37 77201
> michael.eisenring at agroscope.admin.ch<mailto:
> michael.eisenring at agroscope.admin.ch>
> www.agroscope.ch<http://www.agroscope.ch/>
>
>
>         [[alternative HTML version deleted]]
>
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]