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| -rw-r--r-- | r.html.markdown | 1 | 
1 files changed, 1 insertions, 0 deletions
| diff --git a/r.html.markdown b/r.html.markdown index 447db4b3..d3d725d3 100644 --- a/r.html.markdown +++ b/r.html.markdown @@ -259,6 +259,7 @@ levels(infert$education) # "0-5yrs"  "6-11yrs" "12+ yrs"  # NULL  # "NULL" is a weird one; use it to "blank out" a vector  class(NULL)	# NULL +parakeet = c("beak", "feathers", "wings", "eyes")  parakeet  # =>  # [1] "beak"     "feathers" "wings"    "eyes"     | 
