[R] Maintaining specific order when using aggregate or change order on axis

[William Dunlap]

Right after importing your data with read.csv, make a factor out of your
Depth column and give it levels in the desired order.  E.g.,
   SChla$Depth <- factor(SChla$Depth, levels=c("Surface", "Shallow", "Deep", "Fmax", "Below"))
(Capitalization is important, "Below" is not the same as "below".)

To check that things were imported as expect do
   table(SChla$Dept)
before and after the change.  Only the order of the table entries should change.

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
> Of Tinus Sonnekus
> Sent: Tuesday, September 11, 2012 10:52 AM
> To: r-help at r-project.org
> Subject: [R] Maintaining specific order when using aggregate or change order on axis
> 
> Hi All,
> 
> I'm using the following code to produce some stacked bar graphs.
> 
> *setwd("C:\\Users\\Tinus\\Documents\\NMMU\\R\\Seamounts")*
> *SChla <- read.csv("SM_Chla_data.csv")*
> *
> *
> *#Extract mean values from data file*
> *
> *
> *Coral <- SChla[185:223,] #Reduce SChla to Coral only*
> *coral <- with(Coral , aggregate(cbind(Pico, Nano, Micro),
> list(Depth),FUN=mean))*
> *rownames(coral) <- coral[,1] *
> *coral <- t(coral[,-1]) # Remove Station col and transpose*
> 
> *barplot(coral, main="Size fractionated Chl a for Coral", *
> * ylab = "Coral", xlim = c(0,8), horiz = TRUE,*
> * xlab = expression ("Chlorophyll a " ~~ (mu*g ~ l^{-1})), *
> * col =c("light green", "green", "dark green"),*
> * legend = rownames(coral))*
> 
> Here is the *head(Coral) *before station col removal and t()
>     Seamount Station   Depth  Pico  Nano Micro Total_Ch
> 185    Coral    1401 Surface 0.216 3.270 4.240    7.726
> 186    Coral    1401    Fmax 0.359 3.890 4.900    9.149
> 187    Coral    1401   Below 0.178 1.360 1.210    2.748
> 188    Coral    1402 Surface 0.231 4.140 3.670    8.041
> 189    Coral    1402    Fmax 0.863 4.340 3.750    8.953
> 190    Coral    1402   Below 0.176 0.386 0.214    0.776
> 
> So I use the same code for the six other seamounts. The depth has
> the following values  surface, shallow, deep, fmax and below . These are in
> order as you go down the water column. The problem is when I use the *coral
> <- with(Coral , aggregate(cbind(Pico, Nano, Micro), list(Depth),FUN=mean)) *the
> depth values gets stored in ascending values.
> 
> head(coral)
>   Group.1      Pico      Nano     Micro
> 1   Below 0.1652727 0.8610909 0.7227273
> 2    Deep 0.1480000 1.1700000 1.1000000
> 3    Fmax 0.3067273 3.1845455 3.2245455
> 4 Shallow 0.2617500 1.8242500 1.8637500
> 5 Surface 0.1693333 2.7083333 2.7858333
> 
> I would like to maintain the order surface, shallow, deep, fmax and below. *Or
> *if there is a way I can rearrange the yaxis in the order surface, shallow,
> deep, fmax and below.
> 
> Any suggestions?
> 
> Thank you
> Tinus
> 
> --
> M.J. Sonnekus
> PhD Candidate (The Phytoplankton of the southern Agulhas Current Large
> Marine Ecosystem (ACLME))
> Department of Botany
> South Campus
> Nelson Mandela Metropolitan University
> PO Box 77000
> Port Elizabeth
> South Africa
> 6031
> 
> Cell: 082 080 9638
> E-mail: tsonnekus at gmail.com
> 
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> 
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