ffwhich() on ff_matrix

[meowcat]

Hi,

I was trying to use ffwhich(), but it doesn't currently work with ff_matrix objects. ff_matrix objects have classes "ff_matrix" "ff_array" "ff" but not ffdf or ff_vector. Are there technical reasons why this couldn't work? I find it really convenient to do e.g. replacement operations on matrix subsets (since in regular R matrices can be accessed just like regular vectors with a single index).

[jwijffels]

no technical reasons, it's just not implemented yet. feel free to contribute.
Code for ffwhich in ff_vector and ffdf is https://github.com/edwindj/ffbase/blob/master/pkg/R/ffwhich.R
ffwhich.ff_matrix go ahead.