[R] apply( )
Petr Klasterecky
klaster at karlin.mff.cuni.cz
Thu May 10 18:03:44 CEST 2007
ifelse(((x < y) | (x > z)), 1, 0)
Note in particular the use of | instead of || for elementwise comparisons.
Petr
Greg Tarpinian napsal(a):
> I have a question that must have a simple answer (but eludes me).
> I need a row-by-row logical comparison across three numeric variables
> in
> a data frame: foo$x, foo$y, foo$z. The logic is
>
> if( x < y || x > z ) 1 else 0
>
> for a particular row.
>
> It is simple and very inefficient to use for(i in 1:length(foo$x)){ }
> loops. How can I accomplish this using sappy( ) / lapply( ) / apply( )
> or some other more efficient method?
>
> Thank you in advance,
>
> Greg
>
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--
Petr Klasterecky
Dept. of Probability and Statistics
Charles University in Prague
Czech Republic
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