Hello I'm working with R since a few month and have still many trivial questions - I guess! Here is what I want: I have this matrix:> dim(datjan)[1] 899 4 The first 10 rows looks as follows:> datjan[1:10,]V1 V2 V3 V4 1 1961 1 1 24 2 1961 1 2 24 3 1961 1 3 24 4 1961 1 4 24 5 1961 1 5 24 6 1961 1 6 27 7 1961 1 7 27 8 1961 1 8 27 9 1961 1 9 27 10 1961 1 10 27 I tried now to create a for() loop, which gives me the sum of the 30 different classes (1:30!) in [,4]. for(i in 1:30){ sum(datjan[,4]==i) } R is then actually calculating the sum of "i" which certainly doesn't exist and results in a "0" value t1<-sum(datjan[,4]==1) t2<-sum(datjan[,4]==2) .................................until '30' This way its working, but I won't find a end by doing all this by hand, because there are many other matrix waiting. So, how can I make work that loop?? thanks for helping me
Hi Martin, it is slightly unclear to me what you are trying to achieve... are you trying to tabulate how often each value appears in datjan[,4]? Then table(datjan[,4]) may be what you want. HTH Stephan Schmidt Martin schrieb:> Hello > > I'm working with R since a few month and have still many trivial > questions - I guess! Here is what I want: > > I have this matrix: >> dim(datjan) > [1] 899 4 > > The first 10 rows looks as follows: >> datjan[1:10,] > V1 V2 V3 V4 > 1 1961 1 1 24 > 2 1961 1 2 24 > 3 1961 1 3 24 > 4 1961 1 4 24 > 5 1961 1 5 24 > 6 1961 1 6 27 > 7 1961 1 7 27 > 8 1961 1 8 27 > 9 1961 1 9 27 > 10 1961 1 10 27 > > I tried now to create a for() loop, which gives me the sum of the 30 > different classes (1:30!) in [,4]. > > for(i in 1:30){ > sum(datjan[,4]==i) > } > > R is then actually calculating the sum of "i" which certainly doesn't > exist and results in a "0" value > > t1<-sum(datjan[,4]==1) > t2<-sum(datjan[,4]==2) > .................................until '30' > This way its working, but I won't find a end by doing all this by hand, > because there are many other matrix waiting. > > So, how can I make work that loop?? > > thanks for helping me > > ______________________________________________ > 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 - do you want
sum(datjan$V4)
OR
sum(unique(datjan$V4)) ?
there's also a cumsum function that might be useful
hth,
David Freedman, Atlanta
Schmidt Martin wrote:>
> Hello
>
> I'm working with R since a few month and have still many trivial
> questions - I guess! Here is what I want:
>
> I have this matrix:
>> dim(datjan)
> [1] 899 4
>
> The first 10 rows looks as follows:
>> datjan[1:10,]
> V1 V2 V3 V4
> 1 1961 1 1 24
> 2 1961 1 2 24
> 3 1961 1 3 24
> 4 1961 1 4 24
> 5 1961 1 5 24
> 6 1961 1 6 27
> 7 1961 1 7 27
> 8 1961 1 8 27
> 9 1961 1 9 27
> 10 1961 1 10 27
>
> I tried now to create a for() loop, which gives me the sum of the 30
> different classes (1:30!) in [,4].
>
> for(i in 1:30){
> sum(datjan[,4]==i)
> }
>
> R is then actually calculating the sum of "i" which certainly
doesn't
> exist and results in a "0" value
>
> t1<-sum(datjan[,4]==1)
> t2<-sum(datjan[,4]==2)
> .................................until '30'
> This way its working, but I won't find a end by doing all this by
> hand, because there are many other matrix waiting.
>
> So, how can I make work that loop??
>
> thanks for helping me
>
> ______________________________________________
> 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.
>
>
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Hi, I usually use aggregate() for this: aggregate(datjan,list(datjan[,4]),sum) with the advantage that you can use any other aggregation function (mean, var and so on...). See help. Miguel On Sun, Mar 14, 2010 at 8:49 PM, Schmidt Martin <m.schmidt@students.unibe.ch> wrote:> Hello > > I'm working with R since a few month and have still many trivial questions > - I guess! Here is what I want: > > I have this matrix: > >> dim(datjan) >> > [1] 899 4 > > The first 10 rows looks as follows: > >> datjan[1:10,] >> > V1 V2 V3 V4 > 1 1961 1 1 24 > 2 1961 1 2 24 > 3 1961 1 3 24 > 4 1961 1 4 24 > 5 1961 1 5 24 > 6 1961 1 6 27 > 7 1961 1 7 27 > 8 1961 1 8 27 > 9 1961 1 9 27 > 10 1961 1 10 27 > > I tried now to create a for() loop, which gives me the sum of the 30 > different classes (1:30!) in [,4]. > > for(i in 1:30){ > sum(datjan[,4]==i) > } > > R is then actually calculating the sum of "i" which certainly doesn't exist > and results in a "0" value > > t1<-sum(datjan[,4]==1) > t2<-sum(datjan[,4]==2) > .................................until '30' > This way its working, but I won't find a end by doing all this by hand, > because there are many other matrix waiting. > > So, how can I make work that loop?? > > thanks for helping me > > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]