Question

为3D数据结构提供简单的基于文本的文件格式：

d d d d d
d d d d d
d d d d d
d d d d d
d d d d d
-
s s s s s
s s s s s
s s s s s
s s s s s
s s s s s
-
g g g g g
g g g g g
g g g g g
g g g g g
g g g g g
-

表示短字符串的5x5x3数据结构。我想知道如何有效地将这些数据加载到std::vector<std::vector<std::vector<std::string>>>类型的结构中？

到目前为止我试过这个：

std::ifstream file("file.txt"); 
std::vector<std::vector<std::vector<std::string>>> data;

int lines = 0;
std::string line;
while(std::getline(file, line)){        
    std::stringstream stream(line);            
    if (line.size() > 1){
        lines++;
        data.resize(lines);            
        data.back().push_back(std::vector<std::string>());
        std::string val;
        while(stream >> val){
            data.back().back().push_back(val);
        }            
    }              
}

虽然只是在二维中填充3D矢量，但它有些工作。我仍然不确定效率。

Answer 1

也许这段代码很糟糕但是它完成了任务。:)而不是我使用std :: cin的文件。

#include <iostream>
#include <vector>
#include <string>


int main() 
{
    const size_t N = 3;
    const size_t M = 5;

    std::vector<std::vector<std::vector<std::string>>> v;

    v.reserve( N );

    std::vector<std::vector<std::string>> v2;
    v2.reserve( M );
    size_t k = 0;
    do
    {
        v2.clear();

        std::vector<std::string> v1;
        v1.reserve( M );
        size_t j = 0;
        do
        {
            v1.clear(); 
            std::string s;
            for ( size_t i = 0; i < M && std::cin >> s; i++ )
            {
                v1.push_back( s );
            }

            if ( !v1.empty() ) v2.push_back( v1 );
        } while ( ++j < M && !v1.empty() );

        if ( !v2.empty() ) v.push_back( v2 );
    } while ( k < N && ! v2.empty() );

    for ( const std::vector<std::vector<std::string>> &v2 : v )
    {
        for ( const std::vector<std::string> &v1 : v2 )
        {
            for ( const std::string &s : v1 ) std::cout << s << ' ';
            std::cout << std::endl;
        }

        std::cout << std::endl;
    }

    return 0;
}

输出（使用相同的输入）：

"d" "d" "d" "d" "d" 
"d" "d" "d" "d" "d" 
"d" "d" "d" "d" "d" 
"d" "d" "d" "d" "d" 
"d" "d" "d" "d" "d" 

"s" "s" "s" "s" "s" 
"s" "s" "s" "s" "s" 
"s" "s" "s" "s" "s" 
"s" "s" "s" "s" "s" 
"s" "s" "s" "s" "s" 

"g" "g" "g" "g" "g" 
"g" "g" "g" "g" "g" 
"g" "g" "g" "g" "g" 
"g" "g" "g" "g" "g" 
"g" "g" "g" "g" "g"

Answer 2

解决方案变得非常类似于我在问题中展示的内容。虽然做了一些小修改：

std::ifstream file("file.txt");
std::vector<std::vector<std::vector<std::string>>> data;

data.push_back(std::vector<std::vector<std::string>>());
std::string line;
while(std::getline(file, line)){        
    std::stringstream stream(line);            
    if (line.size() > 1){
        data.back().push_back(std::vector<std::string>());
        std::string val;
        while(stream >> val){
            data.back().back().push_back(val);
        }            
    } 
    else {
             array_.push_back(std::vector<std::vector<Entity>>());
    }
}

打印结果：

for (auto v1 : data){
    for (auto v2 : v1){
        for(auto s : v2){
            std::cout << s << " ";
        }
        std::cout << std::endl;
    }
    std::cout << std::endl;     
}

给予：

d d d d d
d d d d d
d d d d d
d d d d d
d d d d d

s s s s s 
... etc

使用C ++将文本文件中的数据读入3D矢量

2 个答案: