[R] Imposing more than one condition to if
Rui Barradas
ruipbarradas at sapo.pt
Wed Jul 18 11:37:50 CEST 2012
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$date, f))
> Again, I attached a dput() with the object z which contains my dataset.
> Santi
>
> *From:* Rui Barradas <ruipbarradas at sapo.pt>
> *To:* Santiago Guallar <sguallar at yahoo.com>
> *Cc:* r-help at r-project.org
> *Sent:* Tuesday, July 17, 2012 11:52 AM
> *Subject:* Re: [R] Imposing more than one condition to if
>
>
> Hello,
>
> My code couldn't find the right input columns because your real
> data has
> different names, it could only find the example dataset's names.
>
> And there's another problem, my code would give correct answers
> with a
> limted number of possible inputs and fail with real data.
>
> Corrected:
>
>
> f <- function(x){
> zrle <- rle(x$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 <ruipbarradas at sapo.pt
> <mailto:ruipbarradas at sapo.pt>>
> > *To:* Santiago Guallar <sguallar at yahoo.com
> <mailto:sguallar at yahoo.com>>
> > *Cc:* r-help at r-project.org <mailto:r-help at 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 at r-project.org <mailto:R-help at r-project.org>
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> > > and provide commented, minimal, self-contained,
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> > >
> >
> >
> >
>
>
>
>
>
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