[R] lattice/ylim: how to fix ylim[1], but have ylim[2] dynamically calculated?

[Johannes Graumann]

David Winsemius wrote:

> 
> On Feb 14, 2010, at 10:33 AM, Johannes Graumann wrote:
> 
>> Hello,
>>
>> When drawing "barcharts", I find it not helpful if ylim[1] != 0 -
>> bars for a
>> quantity of 0, that do not show a length of 0 are quite non-intuitive.
>>
>> I have tried to study
>> > library(lattice)
>> > panel.barchart
>> but am unable to figure out where ylim is taken care of and how one
>> might
>> fix ylim[1] to 0 for barcharts ...
>>
>> Can anyone point out how to tackle this?
> 
> Looking at Sarkar's "Lattice" text in chapter 8 section 3 "Limits and
> Aspect Ratio", it appears from subsection 1 that the prepanel function
> can used to supply values of xlim and ylim values. From subsection 2
> he clarifies that xlim and ylim can also be specified on a per panel
> basis (and here I am guessing that this would be within a scales
> argument) when relation="free". At the end of that section he offers
> two examples using ylim: the first is not plotted but the second uses
> the prepanel mechanism for Fig 8.1 and that is probably available on
> the Lattice website.
> 
> In the same subsection is offered an alternative to specifying an
> explicit scales$y$limits to be interpreted as ylim values.
> 
> My hope it that these ideas and references will be of some use in
> identifying productive places to look for further documentation.

I am quite certain that this is the most elaborately worded version of 
"RTFM" I have ever come across.

I shall go and do so.

Sincerely, Joh