[R] monthly boxplot

[David Winsemius]

On Aug 9, 2011, at 9:46 AM, Fernando Andreacci wrote:

> I'm trying to make a monthly boxplot using this:
>
> boxplot(varmeasure ~ vardates)
>
> vardates = [1] 10/1/2010 10/1/2010 10/1/2010 10/1/2010 10/1/2010  
> 10/1/2010
> 10/1/2010
> [8] 10/1/2010 10/1/2010 11/1/2010 11/1/2010 11/1/2010 11/1/2010  
> 11/1/2010
> ....
>
> varmeasure =  [1]   0.0  26.0   0.2  -0.2  -1.2  -0.8   0.0   4.4   
> -0.6
> -0.2  14.4  -0.2
> [13]   4.8   4.0   2.8   3.2   3.8   3.2 -11.4   0.2   0.4   3.0    
> 0.6   6.2
> ....
>
>
> they have same size.
>
>
> My problem is that R is ploting ordered by months and not by year  
> and by
> months
>
> I'm getting 1/1/2011, 10/1/2010, 11/1/2010, 2/1/2011
>
> How can I plot it in chronological order?

By converting those character strings to dates. At the moment you seem  
to believe that R has the ability to "know" that you want these  
strings to be dates.

?as.Date
?Dates

-- 

David Winsemius, MD
West Hartford, CT