[R] How to select one value per row (different columns) from array
wjm1 at caa.columbia.edu
Wed Mar 1 15:38:15 CET 2017
Building on Peter Dalgaard's code, are you just trying to take a sample of
a random column from each row? You don't need to use apply:
> array[cbind(1:nrow(array), sample.int(ncol(array), nrow(array),
Just a general note, since you're sampling one-column-per-row from an array
with more rows than columns, you'll have to set replace=TRUE. However,
there may be other datasets where you have more columns than rows and never
want to sample each column more than once, in which case you would set
On Wed, Mar 1, 2017 at 5:38 AM, peter dalgaard <pdalgd at gmail.com> wrote:
> On 01 Mar 2017, at 14:28 , Wolfgang Waser <waser at frankenfoerder-fg.de>
> > Dear all,
> > I have to pick one value per row from an array, but from row to row from
> > a different column. The column positions of the values for each row are
> > stored in a vector.
> > array: 999 rows, 48 columns
> > vector: 999 values (each between 1 and 48) indicating for each row which
> > value to pick from that row.
> > Is there a non-loop way to pick the 999 values from the array, probably
> > using some form of ?apply?
> > Thank you very much for help and suggestions!
> > Wolfgang
> > ______________________________________________
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> Peter Dalgaard, Professor,
> Center for Statistics, Copenhagen Business School
> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
> Phone: (+45)38153501
> Office: A 4.23
> Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> PLEASE do read the posting guide http://www.R-project.org/
> and provide commented, minimal, self-contained, reproducible code.
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