On Sep 16, 2011, at 10:36 AM, Ben Ganzfried wrote:
Hi guys,
My code (next 2 lines below) isn't doing what I'm expecting it to:
tmp <-
ifelse(uncurated
$days_to_tumor_recurrence=="null","norecurrence","recurrence")
curated$recurrence_status <- tmp
I want the column "recurrence_status" in my output file to have values
"recurrence" (if the input value had a number in the
days_to_tumor_recurrence column for the particular patient) or
"norecurrence" (if the input value said "null" in the
days_to_tumor_recurrence column for the particular patient).
Part of my above code gives me what I want. My current output file
does
indeed get "recurrence" everywhere it should say this. But for the
input
values of "null" I am getting output values of NA instead of
"norecurrence." I tried the following strategies to solve this and
was
unsuccessful.
First, I added a line in the middle of the two above lines of code,
with the
following:
tmp[tmp==NA] <- "norecurrence"
This did not work.
Second, I changed the first line of my code to:
tmp <-
ifelse(uncurated
$days_to_tumor_recurrence==NA,"norecurrence","recurrence")
I do not know why your original did not succeed but this code should
have been written:
tmp <-
ifelse(is,na(uncurated
$days_to_tumor_recurrence),"norecurrence","recurrence")
Nothing ever "equals" NA. NA is not less than anything. It is not TRUE-
ly greater than anything. However, in one sense it is both less than
anything as well as greater than everything including the infinities, -
Inf and Inf:
> min(c(NA, 1))
[1] NA
> max(c(NA, 1))
[1] NA
> min(c(NA, 1, -Inf))
[1] NA
> min(c(NA, 1, Inf))
[1] NA
Gertrude Stein is once alleged to have commented about Oakland
California, "There's no there there." There is quite a bit there now,
but NA still has "no there there".
This was worse, as was trying:
tmp <-
ifelse(uncurated
$days_to_tumor_recurrence=="NA","norecurrence","recurrence")
I would greatly appreciate any advice you may have. Also, why is this
happening?
Thanks a bunch,
Ben
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David Winsemius, MD
West Hartford, CT
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
