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rinfinity

Distinguishing between infinity and negative infinity during value replacement in R

There are some good examples of how to replace infinite values in R with NA in this thread.

For instance,

DT <- data.table(dat)
invisible(lapply(names(DT),function(.name) set(DT, 
           which(is.infinite(DT[[.name]])), j = .name,value =NA)))

However, this doesn't distinguish between positive (Inf) and negative infinity (-Inf).

I need to make this distinction because instead of just replacing the values with NA and throwing them out or imputing them, I'd like to try using the max non-infinite value for positive infinity and min non-infinity value for negative infinity (and things like that).

Is this possible?

Example input data

a <- c(-1,2,3,4,100/0,-100/0)

[1] -1 2 3 4 Inf -Inf

Example output data

[1] -1 1 2 3 4 4 -1

Solution

  • Why not just combine is.infinite with a standard > or < comparison?

    a <- c(-1,2,3,4,100/0,-100/0)

a[is.infinite(a) & a < 0] <- min(a[!is.infinite(a)])
a[is.infinite(a) & a > 0] <- max(a[!is.infinite(a)])
a
[1] -1  2  3  4  4 -1