[R] conditionally weighted mean with NAs

[Joshua Wiley]

On Sat, Apr 2, 2011 at 7:59 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On Apr 2, 2011, at 10:20 PM, Joshua Wiley wrote:
>> VA <- cbind(OS = c(.2, 0, 1, -.1, NA, 3, NA),
>>  OD = c(.3, -.1, .2, -.1, NA, 0, .1),
>>  Desired = c(0.225, -0.075, 0.4, -0.1, NA, 0.75, 0.1))
>
>  VA <- cbind(VA, 0.75*pmin(VA[, "OS"], VA[, "OD"], na.rm=TRUE) +
>                  0.25*pmax(VA[, "OS"], VA[, "OD"], na.rm=TRUE) )
>
>> VA
>       OS   OD Desired
> [1,]  0.2  0.3   0.225  0.225
> [2,]  0.0 -0.1  -0.075 -0.075
> [3,]  1.0  0.2   0.400  0.400
> [4,] -0.1 -0.1  -0.100 -0.100
> [5,]   NA   NA      NA     NA
> [6,]  3.0  0.0   0.750  0.750
> [7,]   NA  0.1   0.100  0.100
>

That works wonderfully, and it is so elegant!  Thank you, David.

Josh

>
> David Winsemius, MD
> West Hartford, CT
>