通过C ++解析csv [英] parsing csv via C++

问题描述

晚上好，我有以下问题。我这样解析csv文件：

  entry1; entry2; entry3 
 entry4; entry5; entry6 
 ;; 
  

我这样得到条目：

  stringstream iss; 
 while（getline（file，string）{
 iss<< line; 
 while（getline（iss，entry，';'）{
 / do something 
} 
} 
  

但我有一个问题，最后一行）

在这里，我只读了2个条目，需要读取第三个空白条目首先，我应该指出代码中的一个问题，你的 iss 在读取第一行之后处于失败状态，然后调用 while（getline（iss，entry，';'）），所以在读取每一行后你需要重置 stringstream 。它处于失败状态的原因是调用 std：getline（iss，entry，';'）后在流上达到文件结尾。

对于您的问题，一个简单的选项是简单地检查是否有任何东西被读入条目 ：

  stringstream iss; 
 while（getline（file，line））{
 iss< ;线; //如果iss处于失败状态，则此行将失败
 entry =; //清除条目的内容
 while（getline（iss，entry，';'））{
 //做某事
} 
 if（entry == /如果这是真的，没有读入条目
 {
 //没有什么被读入条目，所以做某事
 //这不处理其他情况，所以你需要考虑
 //关于该逻辑的
} 
 iss.clear（）; //<  - 需要在每行后重置流
} 
  

Good evening, I've got the following problem. I am parsing csv file like this:

entry1;entry2;entry3
entry4;entry5;entry6
;;

I'm getting entries this way:

stringstream iss;
while(getline(file, string) {
iss << line;
     while(getline(iss, entry, ';') {
     /do something
     }
}

But I've got a problem with last row (;;) where I did read only 2 entries, I need to read the third blank entry. How can I do it? Thank you very much guys.

解决方案

First, I should point out a problem in the code, your iss is in the fail state after reading the first line and then calling while(getline(iss, entry, ';')), so after reading every line you need to reset the stringstream. The reason it is in the fail state is that the end of file is reached on the stream after calling std:getline(iss, entry, ';')).

For your question, one simple option is to simply check whether anything was read into entry, for example:

stringstream iss;
while(getline(file, line)) {
iss << line; // This line will fail if iss is in fail state
entry = ""; // Clear contents of entry
     while(getline(iss, entry, ';')) {
         // Do something
     }
     if(entry == "") // If this is true, nothing was read into entry
     { 
         // Nothing was read into entry so do something
         // This doesn't handle other cases though, so you need to think
         // about the logic for that
     }
     iss.clear(); // <-- Need to reset stream after each line
}

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