[R] matrix logic
Prof Brian Ripley
ripley at stats.ox.ac.uk
Wed Jan 11 09:15:23 CET 2006
The equality operator is == not =. So you need is.na(data1) == FALSE (F
is a variable, and FALSE is the non-truth value), or, clearer,
ifelse(!is.na(data1), data1, data2)
Another way is
data3 <- data1
data3[is.na(data1)] <- data2[is.na(data1)]
which is more efficient but less clear.
On Tue, 10 Jan 2006, r user wrote:
> I have 2 dataframes, each with 5 columns and 20 rows.
> They are called data1 and data2.I wish to create a
> third dataframe called data3, also with 5 columns and
> 20 rows.
> I want data3 to contains the values in data1 when the
> value in data1 is not NA. Otherwise it should contain
> the values in data2.
> I have tried afew methids, but they do not seem to
> work as intended.:
> Please suggest the best way.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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