R help - May 2012 - creating a new column assigning values of other columns

Hello,
?
I have to create a new column from the values of other columns of a data frame.
The new?column (y$n) is created imposing a condition (using a third variable
y$h) that assigns the values of two time variables (y$b and y$timepos).
Here's the piece of code to get there (using the attached files):
?
xact <- read.table("act.lig", sep = ',',
col.names=c("ok","time","secs","act"))
xlig <- read.table("lig.txt", sep = ',',
col.names=c("ok","time","secs","lig"))
w<- merge(xact, xlig, by = c("time" ,"secs"), all = TRUE,
sort=F)
require(reshape)
z <- cbind(w, colsplit(w$time, split=" ", names=c("date",
"clock")))
zh<-cbind(z, colsplit(z$clock, split=":",
names=c("h","m","s")))
zhd<- cbind(zh, colsplit(zh$date, split="/",
names=c("d","mo","y")))
night <- subset(zhd, zh$lig<6 & zhd$h<9 | zh$lig<6 &
zhd$h>21)
night$timepos<-as.POSIXct(night$time, tz="GMT",
format="%d/%m/%y %H:%M:%S")
a=night$timepos - as.difftime( 1, units="days" )
nighta<-cbind(night,a)
y<- cbind(nighta, b=as.character(a, tz= "GMT", format=
"%Y-%m-%d"))
y$n<-with(y, if (h>=0 & h<9) {b} else {timepos}) ## Missing
warnings
????????????????????????????????????????????????????????????????????????????In
if (h >= 0 & h < 9) { :
????????????????????????????????????????????????????????????????????????????condition
has length > 1 and only the first element will be used
?
How can I go around this problem and get the new column?
?
Thank you,
?
Santi
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Bahhhh -- far too much work to recreate (and I don't think you sent us
the file "act.lig"): here's a much better route:

Go to the step immediately before you're in trouble and use dput() on
your data. R will print out a nice plaintext representation that we
can copy and paste and reproduce *exactly* without having to do all
that you show below.

Incidentally, your warning message suggests you should be using
ifelse() instead of if.

To compare:

x <- seq(-3, 3)
abs.x.wrong <- if(x < 0) -x else x # Warning message gives some hint
abs.x.right <- ifelse(x < 0, -x, x)

Hope this helps,

Michael

On Sat, May 5, 2012 at 5:09 PM, Santiago Guallar <sguallar at yahoo.com>
wrote:
> Hello,
>
> I have to create a new column from the values of other columns of a data
frame. The new?column (y$n) is created imposing a condition (using a third
variable y$h) that assigns the values of two time variables (y$b and y$timepos).
Here's the piece of code to get there (using the attached files):
>
> xact <- read.table("act.lig", sep = ',',
col.names=c("ok","time","secs","act"))
> xlig <- read.table("lig.txt", sep = ',',
col.names=c("ok","time","secs","lig"))
> w<- merge(xact, xlig, by = c("time" ,"secs"), all =
TRUE, sort=F)
> require(reshape)
> z <- cbind(w, colsplit(w$time, split=" ",
names=c("date", "clock")))
> zh<-cbind(z, colsplit(z$clock, split=":",
names=c("h","m","s")))
> zhd<- cbind(zh, colsplit(zh$date, split="/",
names=c("d","mo","y")))
> night <- subset(zhd, zh$lig<6 & zhd$h<9 | zh$lig<6 &
zhd$h>21)
> night$timepos<-as.POSIXct(night$time, tz="GMT",
format="%d/%m/%y %H:%M:%S")
> a=night$timepos - as.difftime( 1, units="days" )
> nighta<-cbind(night,a)
> y<- cbind(nighta, b=as.character(a, tz= "GMT", format=
"%Y-%m-%d"))
> y$n<-with(y, if (h>=0 & h<9) {b} else {timepos}) ## Missing
warnings
>
????????????????????????????????????????????????????????????????????????????In
if (h >= 0 & h < 9) { :
>
????????????????????????????????????????????????????????????????????????????condition
has length > 1 and only the first element will be used
>
> How can I go around this problem and get the new column?
>
> Thank you,
>
> Santi
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
>

Hi Michael,
Yes, I tried ifelse() before but this function returns a numeric value. When I
try to convert it back to POSIXct I get a <NA>*. If I use if else I get a
POSIXct output although it does not return a correct answer (it only returns
y$timepos even when the condition "h<9" fails to be met).
Attached the outputs you suggested (thanks, by the way, I didn't know
dput()). Hope they go through this time.
?
Thank you,
?
Santi
?
*niga$isnight<- as.POSIXct( niga$nit, tz="GMT",
format="%Y-%m-%d %H:%M:%S", origin="2007-06-19" )
?


From: R. Michael Weylandt <michael.weylandt at
gmail.com>
>To: Santiago Guallar <sguallar at yahoo.com> 
>Cc: "r-help at r-project.org" <r-help at r-project.org> 
>Sent: Sunday, May 6, 2012 2:18 AM
>Subject: Re: [R] creating a new column assigning values of other columns
>
>Bahhhh -- far too much work to recreate (and I don't think you sent us
>the file "act.lig"): here's a much better route:
>
>Go to the step immediately before you're in trouble and use dput() on
>your data. R will print out a nice plaintext representation that we
>can copy and paste and reproduce *exactly* without having to do all
>that you show below.
>
>Incidentally, your warning message suggests you should be using
>ifelse() instead of if.
>
>To compare:
>
>x <- seq(-3, 3)
>abs.x.wrong <- if(x < 0) -x else x # Warning message gives some hint
>abs.x.right <- ifelse(x < 0, -x, x)
>
>Hope this helps,
>
>Michael
>
>On Sat, May 5, 2012 at 5:09 PM, Santiago Guallar <sguallar at
yahoo.com> wrote:
>> Hello,
>>
>> I have to create a new column from the values of other columns of a
data frame. The new?column (y$n) is created imposing a condition (using a third
variable y$h) that assigns the values of two time variables (y$b and y$timepos).
Here's the piece of code to get there (using the attached files):
>>
>> xact <- read.table("act.lig", sep = ',',
col.names=c("ok","time","secs","act"))
>> xlig <- read.table("lig.txt", sep = ',',
col.names=c("ok","time","secs","lig"))
>> w<- merge(xact, xlig, by = c("time" ,"secs"),
all = TRUE, sort=F)
>> require(reshape)
>> z <- cbind(w, colsplit(w$time, split=" ",
names=c("date", "clock")))
>> zh<-cbind(z, colsplit(z$clock, split=":",
names=c("h","m","s")))
>> zhd<- cbind(zh, colsplit(zh$date, split="/",
names=c("d","mo","y")))
>> night <- subset(zhd, zh$lig<6 & zhd$h<9 | zh$lig<6
& zhd$h>21)
>> night$timepos<-as.POSIXct(night$time, tz="GMT",
format="%d/%m/%y %H:%M:%S")
>> a=night$timepos - as.difftime( 1, units="days" )
>> nighta<-cbind(night,a)
>> y<- cbind(nighta, b=as.character(a, tz= "GMT", format=
"%Y-%m-%d"))
>> y$n<-with(y, if (h>=0 & h<9) {b} else {timepos}) ##
Missing warnings
>>
????????????????????????????????????????????????????????????????????????????In
if (h >= 0 & h < 9) { :
>>
????????????????????????????????????????????????????????????????????????????condition
has length > 1 and only the first element will be used
>>
>> How can I go around this problem and get the new column?
>>
>> Thank you,
>>
>> Santi
>> ______________________________________________
>> R-help at r-project.org mailing list
>> 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.
>>
>
>
>
>
>