Template Function thrust::sort_by_key(RandomAccessIterator1, RandomAccessIterator1, RandomAccessIterator2, StrictWeakOrdering)

Function Documentation

template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename StrictWeakOrdering>
void thrust::sort_by_key(RandomAccessIterator1 keys_first, RandomAccessIterator1 keys_last, RandomAccessIterator2 values_first, StrictWeakOrdering comp)

sort_by_key performs a key-value sort. That is, sort_by_key sorts the elements in [keys_first, keys_last) and [values_first, values_first + (keys_last - keys_first)) into ascending key order, meaning that if i and j are any two valid iterators in [keys_first, keys_last) such that i precedes j, and p and q are iterators in [values_first, values_first + (keys_last - keys_first)) corresponding to i and j respectively, then *j is not less than *i.

Note: sort_by_key is not guaranteed to be stable. That is, suppose that *i and *j are equivalent: neither one is less than the other. It is not guaranteed that the relative order of these two keys or the relative order of their corresponding values will be preserved by sort_by_key.

This version of sort_by_key compares key objects using a function object comp.

The following code snippet demonstrates how to use

sort_by_key to sort an array of character values using integers as sorting keys. The keys are sorted in descending order using the greater<int> comparison operator.
Pre

The range [keys_first, keys_last)) shall not overlap the range [values_first, values_first + (keys_last - keys_first)).

Parameters

  • keys_first: The beginning of the key sequence.

  • keys_last: The end of the key sequence.

  • values_first: The beginning of the value sequence.

  • comp: Comparison operator.

Template Parameters

  • RandomAccessIterator1: is a model of Random Access Iterator, RandomAccessIterator1 is mutable, and RandomAccessIterator1's value_type is convertible to StrictWeakOrdering's first_argument_type and second_argument_type.

  • RandomAccessIterator2: is a model of Random Access Iterator, and RandomAccessIterator2 is mutable.

  • StrictWeakOrdering: is a model of Strict Weak Ordering.

#include <thrust/sort.h>
...
const int N = 6;
int    keys[N] = {  1,   4,   2,   8,   5,   7};
char values[N] = {'a', 'b', 'c', 'd', 'e', 'f'};
thrust::sort_by_key(keys, keys + N, values, thrust::greater<int>());
// keys is now   {  8,   7,   5,   4,   2,   1}
// values is now {'d', 'f', 'e', 'b', 'c', 'a'}

See

http://www.sgi.com/tech/stl/sort.html

See

stable_sort_by_key

See

sort