Re: [R] Iterations

From: Erik Iverson <iverson_at_biostat.wisc.edu>
Date: Tue, 15 Jul 2008 15:09:46 -0500

Sorry, I'm in ESS.

Try ?Control

rkevinburton_at_charter.net wrote:
> Thank you.
>
> ?for just gives me a + rompt indicating that I need to supply more input. The same with ?while and ?repeat. Help(for) yelds:
>
> > help(for)

> Error: unexpected ')' in "help(for)"
>
> But thanks for the tip.
>
> Keivn
>

> ---- 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 - 20:12:27 GMT

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