[pstricks] read only every third line with \readdata

[Herbert Voss]

Philipp Loosmann wrote:

> in previous messages I read about 'ignore the first n rows' with
> \readdata.
> Is it possible to step over n rows while using \readdata?
> 
> I'm using  `PSTricks-add' v2.73

all possible options are decribed in the documentation.
nStart, nEnd, xStart, ...

Herbert