I think you want to use '%in%' instead of '=='. Try debugging (or
understanding) what is happening by evaluating the subexpressions of
the compares you have in your original posting. Also take a look at
the 'recycling' of arguments and then you may understand what is
happening:
> data2[(data2$x1 %in% data_1$x1) & (data2$y1 %in% data_1$y1) & (data2$tag ==
> 0),]
areaid x1 y1 tag
2 1 1.53 2.34 0
4 1 1.52 2.35 0
>
On Thu, Nov 12, 2009 at 10:04 PM, rusers.sh <rusers...@gmail.com> wrote:
> Hi Rusers,
> I found sometimes that the same values cannot be judged to be the same in
> R. Anybody knows the probelm? I think i ignored some minor detail. Thanks.
> Here is the example.
> ############
> data1<-matrix(data=c(1,1.2,1.3,"3/23/2004",1,1.5,2.3,"3/22/2004",2,0.2,3.3,"4/23/2004",3,1.5,1.3,"5/22/2004"),nrow=4,ncol=4,byrow=TRUE)
> data1<-data.frame(data1);names(data1)<-c("areaid","x","y","date")
> data2<-matrix(data=c(1,1.22,1.32,1, 1.53, 2.34,1, 1.21, 1.37,1, 1.52,
> 2.35,2, 0.21, 3.33,2, 0.23, 3.35,3, 1.57, 1.31,3, 1.59,
> 1.33),nrow=8,ncol=3,byrow=TRUE)
> data2<-data.frame(data2);names(data2)<-c("areaid","x1","y1")
> data2$tag<-0
> data1_1<-data1[1,]
> data2_1<-data2[data2$areaid==data1_1$areaid & data2$tag==0,]
> ran_1<-sample(c(1:length(data2_1)),2, replace = FALSE)
> data2_1<-data2_1[ran_1,]
> data_1<-merge(data1_1,data2_1)
> #data_1
> # areaid x y date x1 y1 tag
> # 1 1 1.2 1.3 3/23/2004 1.52 2.35 0
> # 2 1 1.2 1.3 3/23/2004 1.53 2.34 0
> data2[data_1$x1==data2$x1 & data_1$y1==data2$y1 & data2$tag==0,]
> #data2[c(data_1$x1==data2$x1 & data_1$y1==data2$y1 & data2$tag==0),]
> # areaid x1 y1 tag
> #2 1 1.53 2.34 0
> There should be two same observations between data_1 and data2, but here
> only one was identified.
> Thanks a lot.
>
> --
> -----------------
> Jane Chang
> Queen's
>
> [[alternative HTML version deleted]]
>
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> 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 that you are trying to solve?
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