How to choose only positive values?

Question

I have a dataset which contains positive, negative as well as NA values. How could I select positive-only values using a script? I would also like to replace negatives numbers with NA and leave NA values as they are.

Answer 1

You could use the which function:

sample <- c(1, 2, -7, NA, NaN)
sample[which(sample > 0)]
[1] 1 2

For negative values assign NA.

Using which:

sample[which(sample < 0)] <- NA