[R] break string at specified possitions

[Jan Kacaba]

Nice solution Jim, thank you.



2016-05-12 2:45 GMT+02:00 Jim Lemon <drjimlemon at gmail.com>:
> 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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>>>>> 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 -- 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.