[R] ff objects and ordinary analytical functions.

[Jens Oehlschlägel]

Xiaobo.Gu,
> Can the plenty of analytical functions provided by base R and contributed packages be called with ff objects as parameters directly, or do we have to write special version of the functions for ff objects? If it is the latter case, is there a list of functions which support ff objects already.Xiaobo.Gu
ff is an add-on package that allows you to store and access larger datasets - its not part of the language. 
ff objects have different copy semantics than standard R objects (partially by reference) so it is unlikely that you can write R code that does use ff objects exactly the same way as with standard R objects. 

There is no comprehensive list, but some functions allow ff objects, e.g. 'biglars' which you find if you look at the reverse-dependencies of ff on CRAN. 

Other functions are prepared to handle large datasets in chunks - like 'biglm' - and it is your responsibility to extract those chunks from ff, a database or whatever other source. 

HTH


Jens Oehlschlägel