On May 29, 2013, at 6:27 PM, Peter Lomas wrote:
Hello,
I have a whole bunch of data to two decimal places. I've done some
arithmetic with them, so floating point becomes an issue.
x <- c(1, 0.15,(0.1+.05),0.4)
I want to do something like this:
x[x==0.15]
But you'll notice that is troublesome with the well known floating
point
issue. So really I need to do something like this:
x[all.equal(x, 0.15)]
x[ zapsmall(x-0.15)==0 ]
But that doesn't work because all.equal wants to compare objects and
not
each element.
I could do:
x[round(x,2) ==0.15]
It seems to work in this case, but as I've been working with my data
I'm
concerned its unreliable. What is the most efficient way of
subsetting
data using a machine-tolerance equal numeric value?
Thanks R-Helpers.
David Winsemius, MD
Alameda, CA, USA
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