C++读入"N,X,Y,Z"格式文本文件到Eigen3 Matrix，以及相同格式输出方法

很多数据资料的格式类似这样：

1,-2085738.7757,5503702.8697,2892977.6829
2,-2071267.5135,5520926.7235,2883341.8135
3,-2079412.5535,5512450.8800,2879771.2119
4,-2093693.1744,5511218.2651,2869861.8947
5,-2113681.5062,5491864.0382,2896934.4852
6,-2100573.2849,5496675.0138,2894377.6030

其中数据按照N(点号），X，Y，Z（三维坐标）排序。

这里提供一种C++读入"N,X,Y,Z"格式文本文件到Eigen3 Matrix的方法，以及对应的同格式输出方法

#pragma once#include <fstream>#include <iostream>#include <string>#include <Eigen/Dense>#include <vector>#include <cmath>#include <iomanip>using namespace std;using namespace Eigen;// 字符串分割void SplitString(const std::string& s, std::vector<std::string>& v, const std::string& c){ std::string::size_type pos1, pos2; pos2 = s.find(c); pos1 = 0; while (std::string::npos != pos2) { v.push_back(s.substr(pos1, pos2 - pos1)); pos1 = pos2 + c.size(); pos2 = s.find(c, pos1); } if (pos1 != s.length()) v.push_back(s.substr(pos1));}// 读入相应格式的xyz文件void ReadXYZFile(string filepath, MatrixXd& origin_data){ ifstream infile; infile.open(filepath); cout << "Reading XYZ File: " << filepath << endl; if (!infile.is_open()) { cout << "File Cannot Open" << endl; exit(1); } int r = 0; // 逐行加载数据 char buffer[100]; while (!infile.eof()) { // getline只能读成char*， // 而SplitString只能切割string, // 而atof又只能转化char*到double infile.getline(buffer, 100); // cout << buffer << endl; string line = buffer; if (line == "") { continue; } vector<string> vector_data; SplitString(line, vector_data, ","); for (int c = 0; c < origin_data.cols(); c++) { origin_data(r, c) = atof(vector_data[c].c_str()); } r++; } return;}// 将矩阵按读入的相同格式保存至相应路径void WriteXYZFile(string filepath, MatrixXd& trans_data){ ofstream outfile; outfile.open(filepath, ios::out | ios::trunc); for (int r = 0; r < trans_data.rows(); r++) { for (int c = 0; c < trans_data.cols(); c++) { if (c < trans_data.cols() - 1) { outfile << trans_data(r, c) << ','; } if (c == trans_data.cols() - 1) { outfile << trans_data(r, c); } } outfile << endl; } cout << "Write XYZ File: " << filepath << endl; outfile.close(); return;}

总结

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