On Sep 21, 2009, at 4:50 PM, David Winsemius wrote:
On Sep 21, 2009, at 4:38 PM, Douglas M. Hultstrand wrote:
Hello,
I am deriving near real-time liner relationships based on 5-min
precipitation data, sometimes the non-qced data result in a slope
of NA. I
am trying to read the coefficient (in this example x) to see if it
is equal
to NA, if it is equal to NA assign it a value of 1. I am having
trouble
with the if statement not recognizing the coefficient or "NA" value
in the
test.
Any thoughts, I supplied a really basic example below.
Thank you,
Doug
#####################
###### Example ######
#####################
x=c(1,1,1)
y=c(1,1,1)
fit <- lm(y~x) fit
Call:
lm(formula = y ~ x)
Coefficients:
(Intercept) x
1 NA
coef <- coef(fit) fit$coef[[2]]
[1] NA
if("fit$coef[[2]]" == "NA") {.cw = 1}
And furthermore, don't surround your expressions with quotes unless
that exactly what you wnat to test. Almost surely you wanted to see if
fit$coef[[2]] were equal to <something> rather than "fit$coef[[2]]".
That would test for equality to the string composed of "N" and "A"
but not for NA. (Nothing "equals" NA. )
?is.na
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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