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Function std.algorithm.sorting.topNIndex
Given a range of elements, constructs an index of its top n elements
(i.e., the first n elements if the range were sorted).
Similar to topN, except that the range is not modified.
Prototypes
void topNIndex(alias less, std.algorithm.mutation.SwapStrategy ss, Range, RangeIndex)( Range r, RangeIndex index, SortOutput sorted = SortOutput.no ) if (isRandomAccessRange!Range && isRandomAccessRange!RangeIndex && hasAssignableElements!RangeIndex && isIntegral!(ElementType!RangeIndex)); void topNIndex(alias less, std.algorithm.mutation.SwapStrategy ss, Range, RangeIndex)( Range r, RangeIndex index, SortOutput sorted = SortOutput.no ) if (isRandomAccessRange!Range && isRandomAccessRange!RangeIndex && hasAssignableElements!RangeIndex && is(ElementType!RangeIndex == ElementType!Range*));
Parameters
| Name | Description |
|---|---|
| less | A binary predicate that defines the ordering of range elements.
Defaults to a < b. |
| ss | (Not implemented yet.) Specify the swapping strategy. |
| r | A
random-access range
of elements to make an index for. |
| index | A
random-access range
with assignable elements to build the index in. The length of this range
determines how many top elements to index in index range can either have integral elements, in which case the
constructed index will consist of zero-based numerical indices into
index will be pointers to the top elements in
|
| sorted | Determines whether to sort the index by the elements they refer
to. |
See also
BUGS
The swapping strategy parameter is not implemented yet; currently it is ignored.
Example
// Construct index to top 3 elements using numerical indices: int[] a = [ 10, 2, 7, 5, 8, 1 ]; int[] index = new int[3]; topNIndex(a, index, SortOutput.yes); assert(index == [5, 1, 3]); // because a[5]==1, a[1]==2, a[3]==5 // Construct index to top 3 elements using pointer indices: int*[] ptrIndex = new int*[3]; topNIndex(a, ptrIndex, SortOutput.yes); assert(ptrIndex == [ &a[5], &a[1], &a[3] ]);