Re: [R] Iterations

From: <rkevinburton_at_charter.net>
Date: Tue, 15 Jul 2008 12:29:38 -0700


Sorry I missed the print part. When nothing was output I assumed that nothing happened.

Thank you.

Kevin
---- Erik Iverson <iverson_at_biostat.wisc.edu> wrote:
> If you read the help page, ?for, you might have seen under "Value", that
>
> 'for', 'while' and 'repeat' return the value of the last
> expression evaluated (or 'NULL' if none was), invisibly.
>
> So if you want to see the values, print() them.
>
> In general, from the first part of your message, it looks like you're
> trying to run some analysis on different subgroups of your data.
>
> You may want to try the functions tapply, by, aggregate, ave, etc., for
> this purpose rather than using 'for' loops.
>
> Best,
> Erik Iverson
>
>
> rkevinburton_at_charter.net wrote:
> > I have a command that reads in some data:
> >
> > x <- read.csv("Sales2007.dat", header=TRUE)
> >
> > Then I try to organize the data:
> >
> > sc <- split(x, list(x$Category, x$SubCategory), drop=TRUE)
> >
> > Then I want to iterate through the data. I was able to get the following to run on the R console:
> >
> > for(i in 1:length(sc))
> > {
> > sum(sc[[i]]$Quantity)
> > }
> >
> > But notiing is primted on the console. I find that:
> >
> > for(i in 1:100)
> > {
> > i
> > }
> >
> > Also does't output anything? I am probably making a wrong assumption here. Why desn't the loop seem to output anyything?
> >
> > Thank you.
> >
> > Kevin
> >
> > ______________________________________________
> > 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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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. Received on Tue 15 Jul 2008 - 19:32:17 GMT

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