Slice a string at consecutive indices with R / Rcpp?

Question

I want to write a function that slices a \'string\' into a vector, sequentially, at a given index. I have a fairly adequate R solution for it; however, I figure that writing

Answer 1

I would use substring. Something like this:

strslice <- function( x, n ){   
    starts <- seq( 1L, nchar(x), by = n )
    substring( x, starts, starts + n-1L )
}
strslice( "abcdef", 2 )
# [1] "ab" "cd" "ef"

About your Rcpp code, maybe you can allocate the std::vector with the right size, so that you avoid resizing it which might mean memory allocations, ... or perhaps directly use a Rcpp::CharacterVector. Something like this:

strslice_rcpp <- rcpp( signature(x="character", n="integer"), '
    std::string myString = as(x);
    int cutpoint = as(n);
    int len = myString.length();
    int nout = len / cutpoint ;
    CharacterVector out( nout ) ;
    for( int i=0; i