[R] break string at specified possitions

[Jim Lemon]

Hi again,
Sorry, that should be:

chop_string<-function(x,ends) {
 starts<-c(1,ends[-length(ends)]+1)
 return(substring(x,starts,ends))
}

Jim

On Thu, May 12, 2016 at 10:05 AM, Jim Lemon <drjimlemon at gmail.com> wrote:
> Hi Jan,
> This might be helpful:
>
> chop_string<-function(x,ends) {
>  starts<-c(1,ends[-length(ends)]-1)
>  return(substring(x,starts,ends))
> }
>
> Jim
>
>
> On Thu, May 12, 2016 at 7:23 AM, Jan Kacaba <jan.kacaba at gmail.com> wrote:
>> Here is my attempt at function which computes margins from positions.
>>
>> require("stringr")
>> require("dplyr")
>>
>> ends<-seq(10,100,8)  # end margins
>> test_string<-"Lorem ipsum dolor sit amet, consectetuer adipiscing
>> elit. Aliquam in lorem sit amet leo accumsan lacinia."
>>
>> sekoj=function(ends){
>>   l_ends<-length(ends)
>>   begs=vector(mode="integer",l_ends)
>>   begs[1]=1
>>   for (i in 2:(l_ends)){
>>     begs[i]<-ends[i-1]+1
>>   }
>>   margs<-rbind(begs,ends)
>>   margs<-cbind(margs,c(ends[l_ends]+1,-1))
>>   #rownames(margs)<-c("beg","end")
>>   return(margs)
>> }
>> margins<-sekoj(ends)
>> str_sub(test_string,margins[1,],margins[2,]) %>% print
>>
>> Code to run in browser:
>> http://www.r-fiddle.org/#/fiddle?id=rVmNVxDV
>>
>> 2016-05-11 23:12 GMT+02:00 Bert Gunter <bgunter.4567 at gmail.com>:
>>> Dunno -- but you might have a look at Hadley Wickham's 'stringr' package:
>>> https://cran.r-project.org/web/packages/stringr/stringr.pdf
>>>
>>> Cheers,
>>>
>>> Bert
>>>
>>>
>>> Bert Gunter
>>>
>>> "The trouble with having an open mind is that people keep coming along
>>> and sticking things into it."
>>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>>>
>>>
>>> On Wed, May 11, 2016 at 1:12 PM, Jan Kacaba <jan.kacaba at gmail.com> wrote:
>>>> Dear R-help
>>>>
>>>> I would like to split long string at specified precomputed positions.
>>>> 'substring' needs beginings and ends. Is there a native function which
>>>> accepts positions so I don't have to count second argument?
>>>>
>>>> For example I have vector of possitions pos<-c(5,10,19). Substring
>>>> needs input first=c(1,6,11) and last=c(5,10,19). There is no problem
>>>> to write my own function. Just asking.
>>>>
>>>> Derek
>>>>
>>>> ______________________________________________
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>>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.