[R] unexpected plot behavior

[Martin Renner]

Thank you for the replies, Uwe and Marc. These are explanations that make perfect sense. However, shouldn't the behavior of plot.factor include the option of type = "n" for consistency with the default plot function? 

Best,
Martin



On 21 Apr 2012, at 08:18 , Marc Schwartz wrote:

> On Apr 21, 2012, at 9:49 AM, Martin Renner wrote:
> 
>> When plotting a numerical vector against a factor, 'type="n"' seems to have no affect, e.g. 
>>> plot (1:10~factor (1:10), type = "n")
>> 
>> looks just like
>>> plot (1:10~factor (1:10))
>> 
>> Plotting a numerical against itself works as expected: 
>>> plot (1:10, type = "n")
>> 
>> I see the same behavior under debian gnu/linux, Mac OS X, and Win7 (all current versions, see below). Is this a bug? 
>> 
>> Regards,
>> Martin
> 
> 
> 
> This has to do with method dispatch. See ?plot.formula, which is the plot method called you pass a formula, as opposed to passing a vector as in your third example. 
> 
> In this case, ?plot.factor is called when the 'x' part of the formula (RHS) is a factor. When plot.factor is called, it internally calls ?boxplot and of course, there is no "type = 'n'" for boxplots, hence it is ignored.
> 
> Regards,
> 
> Marc Schwartz
>