[R] ordering a boxplot

[Boris Steipe]

There may be more concise ways to do this - but you are 99% there with your approach:
try:

boxplot(mydata[,names(sort(apply(mydata,2,median)))])

B.


On Mar 21, 2015, at 6:49 PM, Antonio Silva <aolinto.lst at gmail.com> wrote:

> Thanks Bill and David
> 
> Here goes an example
> 
> SP1<-c(9,6,7,8,5,8,7,5,9,7)
> SP2<-c(1,3,4,2,4,2,5,3,2,1)
> SP3<-c(4,6,7,5,7,8,7,6,5,4)
> SP4<-c(5,4,3,5,2,3,4,3,4,2)
> mydata<-data.frame(SP1,SP2,SP3,SP4)
> rownames(mydata)<-c("ST1","ST2","ST3","ST4","ST5","ST6","ST7","ST8","ST9","ST10")
> mydata
> boxplot(mydata)
> 
> Note that this data frame does not have the format Response ~ Group. In my
> real matrix I have up to 40 species.
> 
> Is there any way to have the species ordered by their median abundance (or
> other parameter?)
> 
> The desired order is given by names(sort(apply(mydata,2,median)))
> 
> Thanks once more,
> 
> Antonio Olinto
> Fisheries Institute
> Sao Paulo, Brazil
> 
> 2015-03-21 15:13 GMT-03:00 William Dunlap <wdunlap at tibco.com>:
> 
>> You can use the reorder() function to reorder the grouping vector's
>> factor levels according to a function of the data in each group.  E.g.,
>> compare the following two plots:
>> 
>>   d <- data.frame(Response=cos(1:15), Group=rep(c("A","B","C"),c(6,5,4)))
>>   par(mfrow=c(1,2))
>>   boxplot(Response ~ Group, data=d)
>>   boxplot(Response ~ reorder(Group, X=Response, FUN=median), data=d)
>> 
>> 
>> Bill Dunlap
>> TIBCO Software
>> wdunlap tibco.com
>> 
>> On Fri, Mar 20, 2015 at 2:20 PM, Antonio Silva <aolinto.lst at gmail.com>
>> wrote:
>> 
>>> Hello
>>> 
>>> I'm using a dataframe (mydata) where row names are sampling points and
>>> column names are species in a multivariate analysis.
>>> 
>>> If I write boxplot(mydata) I'll have boxplots for each species abundance
>>> in
>>> alphabetical order.
>>> 
>>> How to get the boxes orderer by the median?
>>> 
>>> Usually for this I write
>>> 
>>> boxplot(value~category,at=rank(tapply(mydata$value,mydata$category,median)))
>>> but for this to work I need a column for the categories and another column
>>> for the values.
>>> 
>>> Thanks in advance, best regards.
>>> 
>>> Antonio Olinto
>>> 
>>>        [[alternative HTML version deleted]]
>>> 
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>>> 
>> 
>> 
> 
> 	[[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.