slice


class
<valarray> 
class slice;

Valarray slice selector

This class represents a valarray slice selector. It does not contain any element - it only describes a selection of elements in a valarray to be used as an index in valarray::operator[] .

A valarray slice is specified 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 separation between the elements in the valarray that are 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.

Members

(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

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
 
// slice example
#include <iostream>
#include <valarray>
using namespace std;

int main ()
{
  valarray<int> foo (12);
  for (int i=0; i<12; ++i) foo[i]=i;

  valarray<int> bar = foo[slice(2,3,4)];

  cout << "slice(2,3,4): ";
  for (size_t n=0; n<bar.size(); n++)
	  cout << bar[n] << ' ';
  cout << endl;

  return 0;
}


Output

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


See also

gslice Valarray generalized slice selector (class)
slice_array Valarray slice selection (class template)