Dear R'helpers,
I guess the solution is trivial but despite some hours of testing and
looking at the doc, I was unable to fix the following problem.
I want to do either:
for (i in 1:lat) a[i,which(a[i,]==0] <- NA
or:
for (i in 1:lat) a[i,which(a[i,]==-9999|a[i,]==9999|a[i,]==9998|a[i,]
==-9998)] <- NA
if the word "Time" is or is not present in variable
"nomfichier":
test<-grep("Time",nomfichier)
the controlling test would be:
if (test==1)
But in either cases I obtain:
if (grep("Time",nomfichier)>0) for (i in 1:lat) a[i,which(a[i,]==0]
<- NA
Erreur : syntax error
> if (grep("Time",nomfichier)<>0) {for (i in 1:lat)
a[i,which(a[i,]
==-9999|a[i,]==9999|a[i,]==9998|a[i,]==-9998)] <- NA}
Erreur : syntax error
>
I would appreciate if someone can show me the right way to do this.
Sincerely
Nicolas
Nicolas Degallier
UMR 7159 / IRD UR182
Laboratoire d'Oc?anographie et du Climat, Exp?rimentation et
Approches Num?riques (LOCEAN)
Tour 45-55, 4e ?t., case 100, 4 place Jussieu
75252 Paris Cedex 5 France
t?l: (33) 01 44 27 51 57
fax: (33) 01 44 27 38 05
E-mail: <Nicolas.Degallier at ird.fr>
pdf reprints (login="anonymous"; password="your at
email.address"):
ftp://ftp.locean-ipsl.upmc.fr/LOCEAN/ndelod
On 2/16/07, Nicolas Degallier <Nicolas.Degallier@ird.fr> wrote:> > Dear R'helpers, > > I guess the solution is trivial but despite some hours of testing and > looking at the doc, I was unable to fix the following problem. > > I want to do either: > > for (i in 1:lat) a[i,which(a[i,]==0] <- NAa[a == 0] <- NA or:> for (i in 1:lat) a[i,which(a[i,]==-9999|a[i,]==9999|a[i,]==9998|a[i,] > ==-9998)] <- NAa[a %in% c(9999, -9999, 9998, -9998)] <- NA if the word "Time" is or is not present in variable "nomfichier":> test<-grep("Time",nomfichier) > > the controlling test would be: > > if (test==1) > > But in either cases I obtain: > > if (grep("Time",nomfichier)>0) for (i in 1:lat) a[i,which(a[i,]==0] > <- NA > Erreur : syntax error > > > if (grep("Time",nomfichier)<>0) {for (i in 1:lat) a[i,which(a[i,] > ==-9999|a[i,]==9999|a[i,]==9998|a[i,]==-9998)] <- NA} > Erreur : syntax error > > > > I would appreciate if someone can show me the right way to do this. > > Sincerely > Nicolas > > Nicolas Degallier > > UMR 7159 / IRD UR182 > Laboratoire d'Océanographie et du Climat, Expérimentation et > Approches Numériques (LOCEAN) > Tour 45-55, 4e ét., case 100, 4 place Jussieu > 75252 Paris Cedex 5 France > tél: (33) 01 44 27 51 57 > fax: (33) 01 44 27 38 05 > > E-mail: <Nicolas.Degallier@ird.fr> > pdf reprints (login="anonymous"; password="your@email.address"): > ftp://ftp.locean-ipsl.upmc.fr/LOCEAN/ndelod > > ______________________________________________ > R-help@stat.math.ethz.ch 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. >-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve? [[alternative HTML version deleted]]
On Fri, 2007-02-16 at 17:10 +0100, Nicolas Degallier wrote:> Dear R'helpers, > > I guess the solution is trivial but despite some hours of testing and > looking at the doc, I was unable to fix the following problem. > > I want to do either: > > for (i in 1:lat) a[i,which(a[i,]==0] <- NA > > or: > for (i in 1:lat) a[i,which(a[i,]==-9999|a[i,]==9999|a[i,]==9998|a[i,] > ==-9998)] <- NAI may be missing something with respect to the structure of 'a'. It would help to know if 'a' is a matrix (seems so). In either case, the following may work: is.na(a) <- (abs(a) >= 9998) | (a == 0) a <- sample(c(-9999, 9999, -9998, 9998, 0, 1:10))> a[1] 0 -9998 8 7 9999 5 10 2 -9999 1 9998 [12] 6 9 3 4 is.na(a) <- (abs(a) >= 9998) | (a == 0)> a[1] NA NA 8 7 NA 5 10 2 NA 1 NA 6 9 3 4 See ?is.na for more information> if the word "Time" is or is not present in variable "nomfichier": > test<-grep("Time",nomfichier) > > the controlling test would be: > > if (test==1) > > But in either cases I obtain: > > if (grep("Time",nomfichier)>0) for (i in 1:lat) a[i,which(a[i,]==0] > <- NA > Erreur : syntax error > > > if (grep("Time",nomfichier)<>0) {for (i in 1:lat) a[i,which(a[i,] > ==-9999|a[i,]==9999|a[i,]==9998|a[i,]==-9998)] <- NA} > Erreur : syntax error > > > > I would appreciate if someone can show me the right way to do this. > > Sincerely > NicolasThe above is also a bit confusing, but let me offer some insight into grep(). If the value is present, then grep() returns the index of the matching value (or the value itself, if "value = TRUE'). If the value is not present, then a 0 length integer or character (depending upon whether 'value' is FALSE or TRUE) is returned. Using the example from ?grep:> txt <- c("arm","foot","lefroo", "bafoobar")> grep("foo", txt)[1] 2 4> grep("foo", txt, value = TRUE)[1] "foot" "bafoobar" However, if the expression is not matched:> grep("MISS", txt)integer(0)> grep("MISS", txt, value = TRUE)character(0) Depending upon what you need to do, you can use any() for a simple boolean result:> any(grep("foo", txt))[1] TRUE> any(grep("MISS", txt))[1] FALSE This could provide an initial filter test to see if the value you require is present in the target vector and if so, then get the actual indices or values in a subsequent call to grep() if needed. In other words, your initial 'if' statement and subsequent code may need to be: if (any(grep("Time", nomfichier))) { is.na(a) <- (abs(a) >= 9998) | (a == 0) } HTH, Marc Schwartz