ESPResSo
Extensible Simulation Package for Research on Soft Matter Systems
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keys.hpp
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1/*
2 * Copyright (C) 2017-2022 The ESPResSo project
3 *
4 * This file is part of ESPResSo.
5 *
6 * ESPResSo is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
10 *
11 * ESPResSo is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20#ifndef UTILS_KEYS_HPP
21#define UTILS_KEYS_HPP
22
23#include <algorithm>
24#include <vector>
25
26namespace Utils {
27/**
28 * @brief Return the keys of a map type.
29 *
30 * Returns a vector of copies of the keys
31 * of a map, unordered_map, ...
32 */
33template <typename Map>
34auto keys(Map const &m) -> std::vector<typename Map::key_type> {
35 using value_type = typename Map::value_type;
36 using std::begin;
37 using std::end;
38
39 std::vector<typename Map::key_type> ret(m.size());
40
41 std::transform(begin(m), end(m), ret.begin(),
42 [](value_type const &kv) { return kv.first; });
43 return ret;
44}
45} // namespace Utils
46
47#endif
auto keys(Map const &m) -> std::vector< typename Map::key_type >
Return the keys of a map type.
Definition keys.hpp:34