> I have written a function in order to analyse gaze paths. It works
> with the test data but when I try to apply the function to a data
> frame that stores "the real data" in columns I receive the error
> message that the
>
> " In if (pp > 1) { :
> condition has length > 1 only the first element will be used
> "
This means that pp is a vector (and hence pp > 1 is also a vector), but
'if' requires a scalar logical value. Try, e.g.
if(1:10 > 5) message("foo")
for a simpler way of recreating this error message.
> I interpret this error message as saying that only the first element
> of pp is used. However, I'd like to analyse each row of the data
> frame, row by row. Using
>
> apply(final, 1, abst, gx,gy,tx,ty,p_pos) (with gx - p_pos being
> columns of the data frame final)
By the looks of things, when you call apply(final, 1, abst,
gx,gy,tx,ty,p_pos), the value of pp (inside the abst function) is being
taken as the value of p_pos, which is all the relevant columns of the data
frame. Are you sure that this is the value you meant for pp?
There is a vectorised version of if, namely the ifelse function. Perhaps
the line if (pp > 1) {px = -px } should be
px <- ifelse(pp > 1, -px, px)
or even more simply,
px[pp > 1] <- -px[pp > 1]
Regards,
Richie.
Mathematical Sciences Unit
HSL
------------------------------------------------------------------------
ATTENTION:
This message contains privileged and confidential inform...{{dropped:20}}
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
