[R] any function in R similar to the "scan" function in SAS?

David Winsemius dwinsemius at comcast.net
Thu May 6 04:22:41 CEST 2010


On May 5, 2010, at 9:17 PM, Gabor Grothendieck wrote:

> You can read from a character vector as if it were a file like this:
>
>> x <- c("1-2", "3-4", "5-6")
>> read.table(textConnection(x), sep = "-", col.names = c("one", "two"))
>  one two
> 1   1   2
> 2   3   4
> 3   5   6
>
>
> On Wed, May 5, 2010 at 12:45 PM, karena <dr.jzhou at gmail.com> wrote:
>>
>> I am wondering if there is any function in R that is similar to the  
>> "scan"
>> function in SAS.
>> I have a data.frame which has two columns as the following:
>> one   two
>> 1      2
>> 3      4
>> 5      6
>>
>> I used the "paste" function to create the third column: three <-
>> paste(one,'-',two,sep="")
>> so the data.frame is like this now:
>> one   two   three
>> 1      2       1-2
>> 3      4       3-4
>> 5      6       5-6

So ... following Grothendieck's lead,  if you wanted to reverse that  
process and assuming your dataframe were named dtxt (and that column  
were text and not factor),  you could read right out of the data.frame:

 > read.table(textConnection(dtxt$three), sep = "-", col.names =  
c("one", "two"))
   one two
1   1   2
2   3   4
3   5   6

Or if you wanted those "appended" as columns:

 > cbind(dtxt, read.table(textConnection(dtxt$three), sep = "-",  
col.names = c("one", "two")) )
   one two three one two
1   1   2   1-2   1   2
2   3   4   3-4   3   4
3   5   6   5-6   5   6

>>
>> My question is, is there any function in R that can do the opposite  
>> thing to
>> what "paste" does?
>> suppose I only have the third column "three" now, and I want to get  
>> the
>> first and second columns. If in SAS, I can do the following:
>> one = scan(three,1,'-')
>> two = scan(three,-1,'-')
>>
>> How can I do this in R?
>>
>> thank you,
>>
>> karena
>> --
>> View this message in context: http://r.789695.n4.nabble.com/any-function-in-R-similar-to-the-scan-function-in-SAS-tp2131264p2131264.html
>> Sent from the R help mailing list archive at Nabble.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 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.

David Winsemius, MD
West Hartford, CT



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