Question

我需要用C ++读取csv文件：文件的第一行包含所有列标题，其余行包含浮点数据（下面的示例，文件已经缩小）。

一些文件有问题，我使用以下代码

#include <iostream>
#include <fstream>
#include <string>

// Compiled and testen on with Clang++ on Ubuntu 14.04
int main(int argc, char** argv) {
    std::ifstream in;
    in.open(argv[1]);

    if(!in.is_open()) {
        std::cerr << "Cannot open file: " << argv[1] << "\n";
        return 1;
    }

    std::string buff;
    std::getline(in, buff);
    while(!in.eof()) {
        std::cout << buff << "\n";
        getline(in, buff);
    }

    in.close();
    return 0;
}

对于大多数文件，这运行正常，每次迭代读取一行; “好”文件的示例：

Time,Smile,AU04,AU02,AU15,Trackerfail,AU18,AU09,negAU12,AU10,Expressive,Unilateral_LAU12,Unilateral_RAU12,AU14,Unilateral_LAU14,Unilateral_RAU14,AU05,AU17,AU26,Forward,Backward
0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,33.333,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,20.0
0.3,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,33.333,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
1.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,33.333,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,16.667,0.0
58.3,50.0,0.0,0.0,0.0,33.333,0.0,0.0,0.0,0.0,100.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
62.4,33.333,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,100.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,20.0

有些文件发疯，并在第一个getline之后设置了eof位。在第一次阅读之后，buff包含第一行的一部分和最后一行的一部分; '坏'文件的示例：

Time,Smile,AU04,AU02,AU15,Trackerfail,AU18,AU09,negAU12,AU10,Occlusion,Expressive,Unilateral_LAU12,Unilateral_RAU12,AU14,Unilateral_LAU14,Unilateral_RAU14,AU05,Au17,AU57,AU58
0,0,0,0,0,16.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
0.3,0,0,0,0,33.333,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
1.3,0,0,0,0,16.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
57.9,66.667,0,0,0,66.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
60.3,33.333,0,0,0,66.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

buff之后调用getline的内容：

Time,Smile,AU04,AU02,AU15,Trackerfail,AU18,AU09,negAU12,AU10,Occlusion,Expressive,Unilateral_LAU12,Unilateral_RAU12,AU14,Unilateral_LAU14,Unilateral_RA60.3,33.333,0,0,0,66.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

如您所见，第一行与最后一行混在一起。我无法弄清楚出了什么问题。每行以\n结尾，文件以空\n结尾。

我想我的问题是：为什么getline在混合第一行和最后一行的同时跳到文件结尾，而其他文件正常工作？

编辑我需要将大数据集转换为更加一致的新格式。当前格式充满了不一致性（使用0和0.0或AU17和Au17）。不过，这些格式化问题不应该只影响阅读文件，对吗？

EDIT2：

cat -v -e -t在好文件上：

Time,Smile,AU04,AU02,AU15,Trackerfail,AU18,AU09,negAU12,AU10,Expressive,Unilateral_LAU12,Unilateral_RAU12,AU14,Unilateral_LAU14,AU05,AU17,AU26,Forward,Backward^M$
0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,66.667,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0^M$
0.2,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,33.333,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0^M$
etc...

错误文件上的

cat -v -e -t：

Time,Smile,AU04,AU02,AU15,Trackerfail,AU18,AU09,negAU12,AU10,Occlusion,Expressive,Unilateral_LAU12,Unilateral_RAU12,AU14,Unilateral_LAU14,Unilateral_RAU14,AU05,Au17,AU57,AU58^M0,0,0,0,0,16.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M0.3,0,0,0,0,33.333,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M1.3,0,0,0,0,16.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M1.4,0,0,0,0,33.333,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M1.8,0,0,0,0,50,0,0,0,0,0,0,0,0,0,0,0,0,0,25,0^M2.8,0,0,0,0,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M3,0,0,0,0,33.333,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M31,0,0,0,0,33.333,0,0,0,0,25,0,0,0,0,0,0,0,0,0,0^M31.1,0,0,0,0,50,0,0,0,0,50,0,0,0,0,0,0,0,0,0,0^M31.2,0,0,0,0,66.667,0,0,0,0,50,0,0,0,0,0,0,0,0,0,0^M31.4,0,0,33.333,0,66.667,0,0,0,0,50,0,0,0,0,0,0,0,0,0,0^M31.5,0,0,33.333,0,66.667,0,0,0,0,50,25,0,0,0,0,0,0,0,0,0^M32,0,0,33.333,0,66.667,0,0,0,0,50,25,0,0,0,0,0,0,0,0,25^M32.1,0,0,33.333,0,83.333,0,0,0,0,50,25,0,0,0,0,0,0,0,0,25^M32.2,0,0,33.333,0,83.333,0,0,0,0,25,25,0,0,0,0,0,0,0,0,25^M32.4,0,0,33.333,0,83.333,0,0,0,0,25,0,0,0,0,0,0,0,0,0,25^M32.7,0,0,33.333,0,83.333,0,0,0,0,0,0,0,0,0,0,0,0,0,0,25^M33,0,0,33.333,0,83.333,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M33.5,0,0,0,0,83.333,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M33.9,0,0,0,0,66.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M55,33.333,0,0,0,66.667,0,0,0,0,0,25,0,0,0,0,0,0,0,0,0^M55.2,66.667,0,0,0,66.667,0,0,0,0,0,25,0,0,0,0,0,0,0,0,0^M55.8,100,0,0,0,66.667,0,0,0,0,0,25,0,0,0,0,0,0,0,0,0^M56.8,100,0,0,0,66.667,0,0,0,0,0,25,0,0,0,0,0,0,0,0,25^M57.4,66.667,0,0,0,66.667,0,0,0,0,0,25,0,0,0,0,0,0,0,0,25^M57.8,66.667,0,0,0,66.667,0,0,0,0,0,25,0,0,0,0,0,0,0,0,0^M57.9,66.667,0,0,0,66.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0^M60.3,33.333,0,0,0,66.667,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

似乎有很大的不同，我该如何解决这个问题？

Answer 1

似乎文件缺少换行符，而是只有回车符（等于^M或 CTRL M ）。

您可以通过对文件使用cat并使用tr管道来将回车符转换为换行符来修复它：

$ cat your-file | tr '\r' '\n' > your-file-fixed

在看到你对来自Max OS的文件的评论后，我认为它是旧的OSX前版本，当Mac OS上的换行只是一次回车。

std :: getline部分读取第一行和最后一行并设置eof-bit

1 个答案: