将python字典翻译为C ++ [英] Translating python dictionary to C++

问题描述

我有一个包含以下代码的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中的所有键并不足以达到我的目的，我想把这段代码翻译成C ++。什么是最好的C ++数据结构用于一个python字典有元组作为其键？什么是C ++等价的上述代码？

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?

我看了boost库中的稀疏矩阵，但是找不到一个简单的方法循环只有非-zero元素。

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

字典将是c ++中的std :: map， 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)] <<'\n';
   }
}

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