receiving Error: unexpected '='

Hi.

It seems to me that you are doing wrong almost everything, sorry.

First to your syntax error. "if" is the function and it needs to be called as such.

new_week <- function(x,y) {
if (x[is.na(x)]) {
x = y
}
}

But if you resolve this you would get

new_week(s1$wk5, s1$wk4)

Error in if (x[is.na(x)]) { : argument is not interpretable as logical
In addition: Warning message:
In if (x[is.na(x)]) { :
  the condition has length > 1 and only the first element will be used

"if" expects logical input but x[is.na(x)] is not logical, it is a selection of values based on logical condition.

But there are more conceptual mistakes. It is not a good idea try to change values of the object inside function. It can be done with ?<<- but I vote strongly against it.

I would change values on fly by
n <- which(is.na(ken$wk5))
ken$wk5[n] <- ken$wk4[n]

or

ken[,6] <- ifelse(is.na(ken[,6]), ken[,5], ken[,6])

or you can put it in function
new_week <- function(colin, colout) {
 ifelse(is.na(ken[,colin]), ken[,colout], ken[,colin])}
}

but there is not much sense in it, as you need to call it like.

ken$wk5 <- new_week(6,5)

Of course, you can modify this function to accept character vectors as subscripts but as I pointed out it does not make much sense to put such simple operation to a function.

Cheers
Petr

-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of KMNanus
Sent: Monday, February 29, 2016 12:09 AM
To: r-help at r-project.org
Subject: [R] receiving Error: unexpected '='

I?m a newbie and trying to execute this simple function in order to
change wk 5 NA?s to wk 4 values for the dataset (ken) below.  Can
someone pls tell me what I?m doing wrong?  The error msg is ?"rror:
unexpected input in "new_week <- function(x,y) { ? Even the ?E? is
missing in the word ?Error."

new_week <- function(x,y) {
if x[is.na(x)] {
x = y
}
}

patient       wk1     wk2     wk3     wk4     wk5
A     1       2       4       6       8
B     2       3       NA      3       17
C     3       4       5       11      NA
D     4       NA      6       12      11
E     5       6       7       NA      21
F     6       7       8       3       NA
G     7       8       9       7       NA



Ken
kmnanus at gmail.com
914-450-0816 (tel)
347-730-4813 (fax)

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