Nice! It works. Thank you, Rui
There's something that takes me back to the original question, though. The code
takes the first value that meets the critical condition (light ==0); however,
this value can appear more than once a day because these animals nest in dark
caves, and once they are in the logger sensor registers a 0. So, a second
condition limiting the time at which the critical condition can be accepted to
calculate dusk should be implemented; something like (although R doesn't allow
to impose the double condition):
if (05:00:00<z$clock> 17:00:00) {zrle <- rle(x$lig == 0)}
Santi
From: Rui Barradas <ruipbarra...@sapo.pt>
>To: Santiago Guallar <sgual...@yahoo.com>
>Cc: r-help@r-project.org
>Sent: Wednesday, July 18, 2012 11:37 AM
>Subject: Re: [R] Imposing more than one condition to if
>
>hELLO,
>
>There was no nedd to change the names of the variables inside the
>fucntion. What was going on s that in this new file column 'dtime'
>doesn't exist. Since column 'clock' exists in all files, I've changed
>the function once again, making it more general.
>
>Note that there is an argument 'colTime' with a default value. In the
>function's use below I call it with and without that argument.
>
>
>f <- function(x, colTime="clock"){
> zrle <- rle(x$lig == 0)
> if(zrle$values[1]){
> idusk <- sum(zrle$lengths[1:2]) + 1
> idawn <- zrle$lengths[1] + 1
> x$dusk <- x[ idusk , colTime ]
> x$dawn <- x[ idawn , colTime ]
> }else{
> idusk <- zrle$lengths[1] + 1
> x$dusk <- x[ idusk , colTime ]
> x$dawn <- NA
> }
> x
>}
>
>str(d)
>#d$date <- as.Date(d$date, format="%d/%m%/y")
>
>#library(chron)
>#tm <- times(as.character(d$clock))
>#d$clock <- tm
>
># See what will happen. This call uses the default 'colTime'
>bb <- by(d, d$date, f)
>for(i in seq_along(bb)) print(head(bb[[i]], 1))
>
># call and rbind. This call uses explicit arg 'colTime'
>do.call(rbind, by(d, d$date, f, colTime="clock"))
>
># Alternatively, it could be, because 'bb' is already created,
>do.call(rbind, bb)
>
>
>In the code above, I use an optional conversion to date and time
>classes; as.Date is part of base R, but class times needs package chron.
>It's a good idea to convert these variables, you can later use, say,
>arithmetics on dates and times, such as differences.
>
>Hope this helps,
>
>Rui Barradas
>
>Em 17-07-2012 19:53, Santiago Guallar escreveu:
>> Thank for your time, Rui.
>> Now, I get this error message:
>> Error en rbind(deparse.level, ...) :
>> numbers of columns of arguments do not match
>> Apparently, some columns have missing values and rbind doesn't work. I
>> tried:
>> require(plyr)
>> do.call(rbind.fill, by(z, z$date, f))
>> Then the code runs through but dusk the variable dusk is missing and
>> dawn is filled with NA.
>> Just in case the problem simply lies in a name, this is your code after
>> I changed the object names (basically 'x' and 'd' by 'z') to adapt them
>> to the names of my dataset:
>> f <- function(z){
>> zrle <- rle(z$lig == 0)
>> if(zrle$values[1]){
>> idusk <- sum(zrle$lengths[1:2]) + 1
>> idawn <- zrle$lengths[1] + 1
>> z$dusk <- z$dtime[ idusk ]
>> z$dawn <- z$dtime[ idawn ]
>> }else{
>> idusk <- zrle$lengths[1] + 1
>> z$dusk <- z$dtime[ idusk ]
>> z$dawn <- NA
>> }
>> z
>> }
>>
>> do.call(rbind, by(z, z$date, f))
>> Again, I attached a dput() with the object z which contains my dataset.
>> Santi
>>
>> *From:* Rui Barradas <ruipbarra...@sapo.pt>
>> *To:* Santiago Guallar <sgual...@yahoo.com>
>> *Cc:* r-help@r-project.org
>> *Sent:* Tuesday, July 17, 2012 11:52 AM
>> *Subject:* Re: [R] Imposing more than one condition to if
>>
>>
>> Hello,
>>
>> My code couldn't find the right input columns because your real
>> data has
>> different names, it could only find the example dataset's names.
>>
>> And there's another problem, my code would give correct answers
>> with a
>> limted number of possible inputs and fail with real data.
>>
>> Corrected:
>>
>>
>> f <- function(x){
>> zrle <- rle(x$lig == 0)
>> if(zrle$values[1]){
>> idusk <- sum(zrle$lengths[1:2]) + 1
>> idawn <- zrle$lengths[1] + 1
>> x$dusk <- x$dtime[ idusk ]
>> x$dawn <- x$dtime[ idawn ]
>> }else{
>> idusk <- zrle$lengths[1] + 1
>> x$dusk <- x$dtime[ idusk ]
>> x$dawn <- NA
>> }
>> x
>> }
>>
>> do.call(rbind, by(d, d$date, f))
>>
>>
>> One more thing, you are reading your dataset into a data.frame
>> forgetting that character strings become factors. Try str(d) to
>> see it.
>> ('d' is the data.frame.) You could/should coerce the date/time
>> values to
>> appropriate classes, something like
>>
>>
>> d$time <- as.character(d$time)
>> d$time <- as.POSIXct(d$time, format="%d/%m/%y %H:%M:%S")
>> d$date <- as.character(d$date)
>> d$date <- as.Date(d$date, format="%d/%m/%y")
>>
>>
>> Hope this helps,
>>
>> Rui Barradas
>>
>> Em 17-07-2012 07:14, Santiago Guallar escreveu:
>> > Thank you Rui,
>> >
>> > When applied to my original data, your code goes through
>> although it
>> > does not produce the correct results: for dusk gives the
>> first time
>> > value of next day, for dawn it gives NA. It seems that the
>> function f
>> > doesn't find the right input columns.
>> > A, Ilso had to push up the memory size.
>> > Attached a file (containing just 3000 of the original c.
>> 45000 rows)
>> > after dput().
>> >
>> > Santi
>> >
>> >
>> >
>>
>>------------------------------------------------------------------------
>> > *From:* Rui Barradas <ruipbarra...@sapo.pt
>> <mailto:ruipbarra...@sapo.pt>>
>> > *To:* Santiago Guallar <sgual...@yahoo.com
>> <mailto:sgual...@yahoo.com>>
>> > *Cc:* r-help@r-project.org <mailto:r-help@r-project.org>
>> > *Sent:* Sunday, July 15, 2012 7:21 PM
>> > *Subject:* Re: [R] Imposing more than one condition to if
>> >
>> > Hello,
>> >
>> > There are obvious bugs in your code, you are testing for
>> light > 2 or
>> > ligth < 2 but this would mean that dusk and dawn are
>> undetermined for
>> > light == 2 and that they happen at light == 1.
>> >
>> > Without loops or compound logical conditions:
>> >
>> >
>> > f <- function(x){
>> > x$dawn <- x$time[ which.min(x$light) ]
>> > x$dusk <- x$time[ max(which(x$light == 0)) + 1 ]
>> > x
>> > }
>> >
>> > do.call(rbind, by(d, d$day, f))
>> >
>> > Hope this helps,
>> >
>> > Rui Barradas
>> >
>> > Em 15-07-2012 17:32, Santiago Guallar escreveu:
>> > > Hi,
>> > >
>> > > I have a dataset which contains several time records for
>> a number
>> > of days, plus a variable (light) that allows to determine
>> night time
>> > (lihgt= 0) and daytime (light> 0). I need to obtain get
>> dusk time
>> > and dawn time for each day and place them in two columns.
>> > >
>> > > This is the starting point (d):
>> > > day time light
>> > > 1 1 20
>> > > 1 12 10
>> > > 1 11 6
>> > > 1 9 0
>> > > 1 6 0
>> > > 1 12 0
>> > > ...
>> > > 30 8 0
>> > > 30 3 0
>> > > 30 8 0
>> > > 30 3 0
>> > > 30 8 8
>> > > 30 9 20
>> > >
>> > >
>> > > And this what I want to get:
>> > > day time light dusk dawn
>> > > 1 1 20 11 10
>> > > 1 12 10 11 10
>> > > 1 11 6 11 10
>> > > 1 9 0 11 10
>> > > 1 6 0 11 10
>> > > 1 12 0 11 10
>> > > ...
>> > > 30 8 0 9 5
>> > > 30 3 0 9 5
>> > > 30 8 0 9 5
>> > > 30 3 0 9 5
>> > > 30 8 8 9 5
>> > > 30 9 20 9 5
>> > >
>> > > This is the code for data frame d:
>> > > day= rep(1:30, each=10)
>> > > n= length(dia); x= c(1:24)
>> > > time= sample(x, 300, replace= T)
>> > > light= rep(c(20,10,6,0,0,0,0,0,8,20), 30)
>> > > d=data.frame(day,time,light)
>> > >
>> > > I'd need to impose a double condition like the next
>> but if does
>> > not take more than one:
>> > > attach(d)
>> > > for (i in 1: n){
>> > > if (light[i-1]>2 & light[i]<2){
>> > > d$dusk<- time[i-1]
>> > > }
>> > > if (light[i-1]<2 & light[i]>2){
>> > > d$dawn<- time[i]
>> > > }
>> > > }
>> > > detach(d)
>> > > d
>> > >
>> > > Thank you for your help
>> > > [[alternative HTML version deleted]]
>> > >
>> > >
>> > >
>> > > ______________________________________________
>> > > R-help@r-project.org <mailto:R-help@r-project.org>
>> <mailto:R-help@r-project.org <mailto:R-help@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
>> <http://www.r-project.org/posting-guide.html>
>> > > and provide commented, minimal, self-contained,
>> reproducible code.
>> > >
>> >
>> >
>> >
>>
>>
>>
>>
>>
>
>
>
>
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