I have a ordered data frame and want to know the number of the last row.
data_ranking <- reduced_data[order(reduced_data$outcome,reduced_data$hospital,na.last=NA),] nobs <- nrow(data_ranking)
gives me different results of
data_ranking <- reduced_data[order(reduced_data$outcome,reduced_data$hospital,na.last=NA),] nobs <- length(data_ranking)
I would like to understand why is that. It seems that nrowgives me the answer I’m looking for, but I don’t understand why.
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