Beware of grep with a list
Another R tip: beware of
as.character applied to a list.
> as.character( list(letters[1:3], letters[4:6]) )
 "c(\"a\", \"b\", \"c\")" "c(\"d\", \"e\", \"f\")"
Really, beware of
grep with a list:
> grep("c", list(letters[1:3], letters[4:6]))
 1 2
You might have thought that the result would be just
grep expects a vector of character strings. If the input is not that, it uses
as.character(). Since the result of that starts with
"c" in each.
See the related discussion (from Sept 2011) on stackoverflow.
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