[R] ordering a boxplot

[David Winsemius]

On Mar 20, 2015, at 2:20 PM, Antonio Silva 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)))

I would not have expected that to succeed. The usual approach is to change the order of factor levels before the call to boxplot.


> but for this to work I need a column for the categories and another column
> for the values.

Yes. That is the usual situation. Since you provide no data we cannot tell what is different about your case.

> 
> Thanks in advance, best regards.
> 
> Antonio Olinto
> 
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> 
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David Winsemius
Alameda, CA, USA