Subset a floating point vector using all.equal?

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)]

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.

Peter

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