[R] Creating dummy variable using ifelse statement while you also retain NA's
wdunlap at tibco.com
Wed Aug 17 21:25:20 CEST 2016
You can use nested ifelse() calls, as in
x <- c("a", "b", NA, "678")
ifelse(is.na(x), NA_integer_, ifelse(grepl("[a-z]", x), 1L, 0L))
# 1 1 NA 0
Note that most modelling functions that need dummy variables
use the model.matrix function internally so character/factor data gets
converted to dummy variables automatically. Using ifelse to make
dummy variables is usually the hard way to do it.
On Wed, Aug 17, 2016 at 11:24 AM, Olu Ola via R-help <r-help at r-project.org>
> Hello,I am trying to create a dummy variable using the ifelse statement.
> However, the ifelse statement does not recognize na.rm = True.
> How can I create a dummy variable so that it still retains the missing
> data denoted as "NA" ?
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