std::slice

class slice;

Valarray slice selector

This class represents a valarray slice selector. It does not contain nor refers to any element - it only describes a selection of elements to be used as an index in valarray::operator[].

A valarray slice is defined by a starting index, a size, and a stride.

The starting index (start) is the index of the first element in the selection.
The size (size) is the number of elements in the selection.
The stride (stride) is the span that separates the elements selected.

Therefore, a slice with a stride higher than 1 does not select contiguous elements in the valarray; For example, slice(3,4,5)selects the elements 3, 8, 13 and 18.

Member functions

(constructor)

slice constructor (public member function )

slice::start

Return start of slice (public member function )

slice::size

Return size of slice (public member function )

slice::stride

Return stride of slice (public member function )

Example

12345678910111213141516171819

// slice example#include <iostream>     // std::cout#include <cstddef>      // std::size_t#include <valarray>     // std::valarray, std::sliceint main (){  std::valarray<int> foo (12);  for (int i=0; i<12; ++i) foo[i]=i;  std::valarray<int> bar = foo[std::slice(2,3,4)];  std::cout << "slice(2,3,4):";  for (std::size_t n=0; n<bar.size(); n++)  std::cout << ' ' << bar[n];  std::cout << '\n';  return 0;}

Edit & Run

Output

slice(2,3,4): 2 6 10