c++ - 仅将 .arff 文件中的某些数据行读入结构 C++

Question

我有一个看起来像这样的 .arff 文件

% Title: Database for fitting contact lenses
% 
% Number of Instances: 24
% 
% Number of Attributes: 4 (all nominal)
% 
% Attribute Information -- 3 Classes:
%   1 : the patient should be fitted with hard contact lenses,
%   2 : the patient should be fitted with soft contact lenses,
%   3 : the patient should not be fitted with contact lenses.
%  
% Class Distribution:
%    1. hard contact lenses: 4
%    2. soft contact lenses: 5
%    3. no contact lenses: 15

@relation contact-lenses

@attribute age          {young, pre-presbyopic, presbyopic}
@attribute spectacle-prescrip   {myope, hypermetrope}
@attribute astigmatism      {no, yes}
@attribute tear-prod-rate   {reduced, normal}
@attribute contact-lenses   {soft, hard, none}

@data
%
% 24 instances
%
young,myope,no,reduced,none
young,myope,no,normal,soft
young,myope,yes,reduced,none
young,myope,yes,normal,hard
young,hypermetrope,no,reduced,none
young,hypermetrope,no,normal,soft
young,hypermetrope,yes,reduced,none
young,hypermetrope,yes,normal,hard
pre-presbyopic,myope,no,reduced,none
pre-presbyopic,myope,no,normal,soft
pre-presbyopic,myope,yes,reduced,none
pre-presbyopic,myope,yes,normal,hard
pre-presbyopic,hypermetrope,no,reduced,none
pre-presbyopic,hypermetrope,no,normal,soft
pre-presbyopic,hypermetrope,yes,reduced,none
pre-presbyopic,hypermetrope,yes,normal,none
presbyopic,myope,no,reduced,none
presbyopic,myope,no,normal,none
presbyopic,myope,yes,reduced,none
presbyopic,myope,yes,normal,hard
presbyopic,hypermetrope,no,reduced,none
presbyopic,hypermetrope,no,normal,soft
presbyopic,hypermetrope,yes,reduced,none
presbyopic,hypermetrope,yes,normal,none

我只想读取上面有数据的行，例如

young,myope,no,reduced,none
young,myope,no,normal,soft
young,myope,yes,reduced,none

进入一个结构。该结构对 5 条数据中的每条数据都有一个字符串成员。我如何编写循环或循环组合，以跳过我不关心的行，并将我正在寻找的数据读入结构？

编辑:我只想读取不以 %、@ 或空行开头的行。我不明白为什么这不起作用。

while(inFile.good())
{
    getline(inFile,line);

    if((line[0] == '%') || (line[0] == '@') || (line[0] == ' '))
    {
        cout << "This line we dont care about" << endl;
    }

    else
    {
        cout << "Made it into the else" << endl;
        getline(inFile,line,',');
        data[count].age = line;
        cout << "data[0] = " << data[count].age << endl;
        getline(inFile,line,',');
        data[count].prescription = line;
        cout << "data[0] = " << data[count].prescription << endl;
        getline(inFile,line,',');
        data[count].astig = line;
        getline(inFile,line,',');
        data[count].tearProduction = line;
        getline(inFile,line);
        data[count].contacts = line;

        count++;
    }

}

Answer 1

这是一个让您入门的示例:

std::string text_line;
while (std::getline(my_data_file, text_line)
{
  // Check the line length first.  Empty lines are ignored.
  if (text_line.length() == 0)
  {
    continue;
  }

  // Test lines for rejection by reading the first character.
  const char c = text_line[0];
  if ((c == '@') || (c == '%') || (c == ' '))
  {
    continue;
  }
  // Add code to parse the data lines
}

continue 将导致执行转到 while 循环的顶部，从而忽略该行。