将python字典翻译成C++

2022-01-19 00:00:00 python dictionary tuples c++

我有包含以下代码的 python 代码.

I have python code that contains the following code. 

d = {}

d[(0,0)] = 0
d[(1,2)] = 1
d[(2,1)] = 2
d[(2,3)] = 3
d[(3,2)] = 4

for (i,j) in d:
    print d[(i,j)], d[(j,i)]

不幸的是，循环遍历 python 中的所有键对于我的目的来说还不够快，我想将此代码转换为 C++.用于以元组为键的 python 字典的最佳 C++ 数据结构是什么?上述代码的 C++ 等价物是什么?

Unfortunately looping over all the keys in python isn't really fast enough for my purpose, and I would like to translate this code to C++. What is the best C++ data structure to use for a python dictionary that has tuples as its keys? What would be the C++ equivalent of the above code?

我查看了 boost 库中的稀疏矩阵，但找不到一种仅循环非零元素的简单方法.

I looked at sparse matrices in the boost library, but couldn't find an easy way to loop only over the non-zero elements.

推荐答案

字典是 c++ 中的 std::map，而包含两个元素的元组是 std::pair.

A dictionary would be a std::map in c++, and a tuple with two elements would be a std::pair.

提供的 python 代码将转换为:

The python code provided would translate to:

#include <iostream>
#include <map>

typedef std::map<std::pair<int, int>, int> Dict;
typedef Dict::const_iterator It;

int main()
{
   Dict d;

   d[std::make_pair(0, 0)] = 0;
   d[std::make_pair(1, 2)] = 1;
   d[std::make_pair(2, 1)] = 2;
   d[std::make_pair(2, 3)] = 3;
   d[std::make_pair(3, 2)] = 4;

   for (It it(d.begin()); it != d.end(); ++it)
   {
      int i(it->first.first);
      int j(it->first.second);
      std::cout <<it->second <<' '
                <<d[std::make_pair(j, i)] <<'
';
   }
}

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