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)
Your syntax on the 'if' is wrong; you need 'if (..expression..)'
-- you are
missing the parentheses. Also read up on functions; any changes are local
-- you cannot change values outside the environment. You should just
return values. You also probably need to pass in the dataframe you want to
make changes to.
Probably what you want is:
new_week <- function(df, x, y){
# x & y are character strings with the names of the columns to
check/change
df[[x]][is.na(df[[x]])] <- df[[y]][is.na(df[[x]])]
df # return value
}
# then call with assignment of the result
df <- new_week(df, 'wk5', 'wk4')
Jim Holtman
Data Munger Guru
What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.
On Sun, Feb 28, 2016 at 6:08 PM, KMNanus <kmnanus at gmail.com> wrote:
> 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)
>
>
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
[[alternative HTML version deleted]]
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)
>
>
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.
________________________________
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"if" is not vectorized... it only works on length 1 test values.
However, if you do use it, it absolutely requires parentheses... if ( test ) {
truecode }.
I think you want "ifelse" which is vectorized... something like
ifelse( is.na( x ), y, x )
Read the help pages ?if and ?ifelse.
I don't know about the missing "E" in the error message... you
might have corrupted your code with unicode or other non-ASCII characters by
using a word processor rather than a text editor.
--
Sent from my phone. Please excuse my brevity.
On February 28, 2016 3:08:56 PM PST, KMNanus <kmnanus at gmail.com>
wrote:>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)
>
>
>
>______________________________________________
>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
[[alternative HTML version deleted]]
Please keep the mailing list cc'd.
Why? Because that is what you are giving it... vectors, and that is how it is
defined to work. Type
?ifelse
at the R console and read the help.
There are several ways to modify a data frame. Some are
ken$wk5 <- ifelse( is.na( ken$wk5 ), ken$wk4, ken$wk5 )
ken$wk5 <- with( ken, ifelse( is.na( wk5 ), wk4, wk5 ) )
ken <- within( ken, {
wk5 <- ifelse( is.na( wk5 ), wk4, wk5 )
})
The ? shortcut to help is your friend.
--
Sent from my phone. Please excuse my brevity.
On February 29, 2016 1:34:56 PM PST, KMNanus <kmnanus at gmail.com>
wrote:>Jeff -
>
>Can you explain why ?ifelse? returns a vector?
>
>When I call > ken2 <- ifelse(is.na(ken$wk5), ken$wk4, ken$wk5)
>
>this is what?s returned - the values are correct but, obviously, I have
>to put it back into the df.
>
>> ken2
>[1] 8 17 11 11 21 3 7
>
>Ken
>kmnanus at gmail.com
>914-450-0816 (tel)
>347-730-4813 (fax)
>
>
>
>> On Feb 29, 2016, at 4:15 PM, KMNanus <kmnanus at gmail.com>
wrote:
>>
>> Jeff -
>>
>> ifelse is clearly the answer. It works nicely and returns a vector
>which I can then reinsert into the data frame. Is there a way that I
>can combine both steps - replacement of the NA?s and reinsertion into
>the data frame - at one time or am I better off just writing a function
>to do that?
>>
>>
>> Ken
>> kmnanus at gmail.com <mailto:kmnanus at gmail.com>
>> 914-450-0816 (tel)
>> 347-730-4813 (fax)
>>
>> <image001.jpg>
>>
>>> On Feb 29, 2016, at 5:17 AM, Jeff Newmiller
><jdnewmil at dcn.davis.ca.us <mailto:jdnewmil at
dcn.davis.ca.us>> wrote:
>>>
>>> "if" is not vectorized... it only works on length 1 test
values.
>However, if you do use it, it absolutely requires parentheses... if (
>test ) { truecode }.
>>>
>>> I think you want "ifelse" which is vectorized...
something like
>>>
>>> ifelse( is.na <http://is.na/>( x ), y, x )
>>>
>>> Read the help pages ?if and ?ifelse.
>>>
>>> I don't know about the missing "E" in the error
message... you might
>have corrupted your code with unicode or other non-ASCII characters by
>using a word processor rather than a text editor.
>>> --
>>> Sent from my phone. Please excuse my brevity.
>>>
>>> On February 28, 2016 3:08:56 PM PST, KMNanus <kmnanus at
gmail.com
><mailto:kmnanus at gmail.com>> wrote:
>>> 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 <http://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 <mailto:kmnanus at gmail.com>
>>> 914-450-0816 (tel)
>>> 347-730-4813 (fax)
>>>
>>>
>>>
>>>
>>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more,
see
>>> https://stat.ethz.ch/mailman/listinfo/r-help
><https://stat.ethz.ch/mailman/listinfo/r-help>
>>> PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
><http://www.r-project.org/posting-guide.html>
>>> and provide commented, minimal, self-contained, reproducible code.
>>
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