(This article was first published on

**One Tip Per Day**, and kindly contributed to R-bloggers)If you also favor to use the function, be aware of the returned value. For example:

Here is another nice example (from http://rwiki.sciviews.org/doku.php?id=tips:programming:ifelse)

> varD <- log(0:9) # A vector like this one that contains -Inf could be troublesome in subsequent manipulations

> varD

[1] -Inf 0.0000000 0.6931472 1.0986123 1.3862944 1.6094379 1.7917595

[8] 1.9459101 2.0794415 2.1972246

> varD <- ifelse(is.finite(varD), varD, NA) # Remove the -Inf, replace with NA

> varD

[1] NA 0.0000000 0.6931472 1.0986123 1.3862944 1.6094379 1.7917595

[8] 1.9459101 2.0794415 2.1972246

To

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