[R] difference between createPartition and createfold functions

[Max Kuhn]

Basically, createDataPartition is used when you need to make one or
more simple two-way splits of your data. For example, if you want to
make a training and test set and keep your classes balanced, this is
what you could use. It can also make multiple splits of this kind (or
leave-group-out CV aka Monte Carlos CV aka repeated training test
splits).

createFolds is exclusively for k-fold CV. Their usage is simular when
you use the returnTrain = TRUE option in createFolds.

Max

On Sun, Oct 2, 2011 at 4:00 PM, Steve Lianoglou
<mailinglist.honeypot at gmail.com> wrote:
> Hi,
>
> On Sun, Oct 2, 2011 at 3:54 PM,  <bby2103 at columbia.edu> wrote:
>> Hi Steve,
>>
>> Thanks for the note. I did try the example and the result didn't make sense
>> to me. For splitting a vector, what you describe is a big difference btw
>> them. For splitting a dataframe, I now wonder if these 2 functions are the
>> wrong choices. They seem to split the columns, at least in the few things I
>> tried.
>
> Sorry, I'm a bit confused now as to what you are after.
>
> You don't pass in a data.frame into any of the
> createFolds/DataPartition functions from the caret package.
>
> You pass in a *vector* of labels, and these functions tells you which
> indices into the vector to use as examples to hold out (or keep
> (depending on the value you pass in for the `returnTrain` argument))
> between each fold/partition of your learning scenario (eg. cross
> validation with createFolds).
>
> You would then use these indices to keep (remove) the rows of a
> data.frame, if that is how you are storing your examples.
>
> Does that make sense?
>
> -steve
>
> --
> Steve Lianoglou
> Graduate Student: Computational Systems Biology
>  | Memorial Sloan-Kettering Cancer Center
>  | Weill Medical College of Cornell University
> Contact Info: http://cbio.mskcc.org/~lianos/contact
>
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-- 

Max