Say I have a dataframe for plotting scatterplot. The dataframe would be
organized in the following fashion (in CSV format):

name ABC EFG1    32  452    56  67
to, say 200 000 entries

I am going to first do a scatterplot, after which I am going to subset a
portion of the dataset into A using alphahull and export them as XYZ. The
script for doing this:

#plot first plot containing all data
plot(x = X$ABC,
y = X$EFG,
pch=20,)
#subset data using ahull. choose 4 points on the plot
A <- ahull(locator(4, type="p", pch=20), alpha=10000)
#exporting subset
XYZ <- {}for (i in 1:nrow(X)) { if (inahull(A, c(X$ABC[i],X$EFG[i])))
XYZ <- rbind(X,X[i,])}

I am getting the following message if the number of data points in the
subset that I choose is too large:Error in if (p[2] > a + b * p[1]) { :
missing value where TRUE/FALSE needed


Does anyone know what might be causing the problem? Any help is much
appreciated!

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