For the record:
...
------------
>
> A bit of commentary: Something did happen. It's just that you didn't do
> anything with _what_ happened. The copy of the 'dataset'-object got modified
> but you never returned it from the function, and and also didn't reassign it
> to the original 'dataset'. Functions return their last assignment. In the
> case of the 'for'-function, it somewhat surprisingly returns a NULL. It is a
> rather odd function in the functional R world, since its main role in life is
> doing things by side-effects,
---------
for() is **not** a function.
?"for" describes it as a "basic control-flow [sic] construct."
Ergo, it's behavior is not odd.
Cheers,
Bert
and so when used inside functions has seemingly paradoxical behavior.
Check your results with:
>
> rename_columns <- function(dataset) {
> for (i in 2:(ncol(dataset))) {names(dataset)[i] <- paste(names(dataset)[1],
> names(dataset)[i], sep="_")
> }
> dataset}
>
> dataset <- rename_columns(dataset)
>
>> [[alternative HTML version deleted]]
>
> And do learn to post in plain text.
>>
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>
> David Winsemius
> Alameda, CA, USA
>
> ______________________________________________
> 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.
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
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