[R] string-to-number SUMMARY

[Gabor Grothendieck]

On 8/19/06, Charles Annis, P.E.
<Charles.Annis at statisticalengineering.com> wrote:
> Much gratitude to Professor Ripley, Peter Dalgaard, Marc Schwartz, and Roger
> Bivand.
> __________________
>
> Roger Bivand wrote that ... strsplit() returns a list - one list component
> for each repeated.measures.columns element. Just pick off the one you want
> with
> [[]]:
> as.numeric(strsplit(repeated.measures.columns, split = ",")[[1]])
>
> which had stumped me, since that syntax fails without the [[1]]
> specification.
> __________________
> Peter Dalgaard, who also suggested the [[1]] specification, pointed out that
>
> scan(textConnection(x), sep=",")
>
> will work, although that leaves you with a dangling open connection.

You do this:

scan(textConnection(x), sep = ",")
closeAllConnections()

Now the following shows that none are open:

showConnections()

You could alternately explicitly close it:

scan(con <- textConnection(x), sep = ",")
close(con)

> __________________
> Marc Schwartz advised to ...
> Use unlist() to take the output of strsplit() and convert it to a vector,
> before coercing to numeric.
>
> as.numeric(unlist(strsplit(repeated.measures.columns, ",")))
> ____________________________________
> Brian D. Ripley suggested that the following looks competitive, and is quite
> a bit more general (e.g. allows spaces, works with complex numbers)
>
> eval(parse(text=paste("c(", repeated.measures.columns, ")")))
>
> and Marc Schwartz showed that Professor Ripley's suggestion is much faster
> than the competition with some system.time trials.
> ____________________________________
>
> Many thanks to all.
>
>
> Charles Annis, P.E.
>
> Charles.Annis at StatisticalEngineering.com
> phone: 561-352-9699
> eFax:  614-455-3265
> http://www.StatisticalEngineering.com
>
>
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Charles Annis, P.E.
> Sent: Saturday, August 19, 2006 7:59 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] string-to-number
>
> Greetings, Amigos:
>
> I have been trying without success to convert a character string,
> > repeated.measures.columns
> [1] "3,6,10"
>
> into c(3,6,10) for subsequent use.
>
> as.numeric(repeated.measures.columns) doesn't work (likely because of the
> commas)
> [1] NA
> Warning message:
> NAs introduced by coercion
>
> I've tried many things including
> strsplit(repeated.measures.columns, split = ",")
>
> which produces a list with only one element, viz:
> [[1]]
> [1] "3"  "6"  "10"
>
> as.numeric() doesn't like that either.
>
> Clearly: 1) I cannot be the first person to attempt this, and 2) I've made
> this WAY harder than it is.
>
> Would some kind soul please instruct me (and perhaps subsequent searchers)
> how to convert the elements of a string into numbers?
>
> Thank you.
>
>
> Charles Annis, P.E.
>
> Charles.Annis at StatisticalEngineering.com
> phone: 561-352-9699
> eFax: 614-455-3265
> http://www.StatisticalEngineering.com
>
>
> ______________________________________________
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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.
>
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>