对于文件比较复杂的时候，为了获取文件中的信息，需要一些比较特殊的函数，比如，getline()、replace（）、atoi,atof等

例子一，读取以下文件中的数据，并保存进一个类里面。

首先，类的定义如下，感觉是struct，但是按照struct的处理，我这段代码出错了，不知道什么问题，暂时po出来吧，有空看看。

struct ImageLabel{ std::string imagePath;//save图片路径名 int faceBox[4];//输入点集的最外层包络矩形rect四个参数 int landmarkPos[2*LandmarkPointsNum];//输入点集private: friend class cereal::access; /** * Serialises this class using cereal. * * @param[in] ar The archive to serialise to (or to serialise from). */ template<class Archive> void serialize(Archive& ar) { ar(imagePath, faceBox, landmarkPos); }};

然后读入一系列如下文件，每个文件的数据保存格式相同，因此定义了一个vector，来顺序存储每一个文件对应的类

文件如下：*.pts文件

version: 1n_points: 68{446.000 91.000449.459 119.344450.957 150.614460.552 176.986471.486 202.157488.087 226.842506.016 246.438524.662 263.865553.315 271.435578.732 266.260599.361 248.966615.947 220.651627.439 197.999635.375 179.064642.063 156.371647.302 124.753646.518 92.944470.271 117.870486.218 109.415503.097 114.454519.714 120.090533.680 127.609571.937 123.590585.702 117.155602.344 109.070620.077 103.951633.964 111.236554.931 145.072554.589 161.106554.658 177.570554.777 194.295532.717 197.930543.637 202.841555.652 205.483565.441 202.069576.368 197.061487.474 136.436499.184 132.337513.781 133.589527.594 143.047513.422 144.769499.117 144.737579.876 140.815590.901 130.008605.648 128.376618.343 132.671606.771 140.525593.466 141.419519.040 229.040536.292 221.978}

所有pts文件名都保存在一个TXT文件中，对应的图像名也保存在一个TXT文件中，我们需要把图片的文件路径加文件名保存到类里面，为了处理方便我们用了replace函数，直接替换pts文件名的的后三位，得到新的文件名。

void readpic(std::vector<ImageLabel> &Imagelabels){ cout<<"test readpic"<<endl; string filePath = "/Users/anitafang/Downloads/Datasets/300W/300w/01_Indoor/"; //打开png图片名存储的TXT文件 ifstream pngfile; pngfile.open("/Users/anitafang/Downloads/Datasets/300W/300w/01_Indoor/pnglist.txt"); if(!pngfile.is_open()){ cout<<"不能打开文件!"<<endl; } //ImageLabel* mImageLabel = NULL;//保存图像信息的类 string line;//读取文件的每一行 while(getline(pngfile,line)){ //mImageLabel = new ImageLabel(); ImageLabel mImageLabel; //mImageLabel->imagePath=filePath+line;//将文件全路径保存在 mImageLabel->imagePath mImageLabel.imagePath=filePath+line;//将文件全路径保存在 mImageLabel->imagePath cout<<line<<endl; //得到pts文件路径 string ress="pts"; string ptss=filePath+line.replace(11,3,ress); cout<<line.replace(11,3,ress)<<endl; cout<<ptss<<endl; //读取pts文件里面的数据 std::ifstream LabelsFile(ptss, std::ios::in); if(!LabelsFile.is_open()) return; //开始读取pts文件内容 int index=0; vector<Point2f> vp2f; char line11[1024]={0};//存放每行数据 //将文件逐行读取到string linestr中，然后对行的内容进行判断 while(LabelsFile.getline(line11, sizeof(line11))){ //从第四行开始把数据写进landmark数组中 if((index>=3)&&(index<139)){ string x = ""; string y = ""; std::stringstream word(line11); word >> x; word >> y; cout<<atof(x.c_str())<<" "<<atof(y.c_str())<<endl; mImageLabel.landmarkPos[index-3] =atof(x.c_str()); mImageLabel.landmarkPos[index+LandmarkPointsNum-3] =atof(y.c_str()); vp2f.push_back(Point2f(mImageLabel.landmarkPos[index-3],mImageLabel.landmarkPos[index+LandmarkPointsNum-3])); cout<<"x:"<<mImageLabel.landmarkPos[index-3]<<" y:"<<mImageLabel.landmarkPos[index+LandmarkPointsNum-3]<<endl; } index++; } Rect rect = boundingRect(vp2f); //根据得到的矩形 输入到facebox中 mImageLabel.faceBox[0] = rect.x; mImageLabel.faceBox[1] = rect.y; mImageLabel.faceBox[2] = rect.width; mImageLabel.faceBox[3] = rect.height; cout<<"facebox"<<mImageLabel.faceBox[0]<<mImageLabel.faceBox[1]<<mImageLabel.faceBox[2]<<mImageLabel.faceBox[3]<<endl; // close file LabelsFile.close(); //free the object Imagelabels.push_back(mImageLabel); //mImageLabel == NULL; }}

其中，因为GetLine读出来的数据是string类型，因此需要将数据转成int型，看到pts文件中数据是都是float型，因此先要将string转成float，用的是atof函数。

另外如果把 Imagelabels 当做类来处理只需要，最开始，ImageLabel mImageLabel;后面直接push_back，不需要delete。所有的引用都变成：mImageLabel.faceBox，不能用mImageLabel->landmarkPos。

另外一个升级的例子，处理起来很复杂，这里把ImageLabel当做一个struct来处理，这样需要new，也需要delete,引用的时候也是用的->，这个需要注意。

文件是：labels_ibug_300W.xml

稍微看一部分，了解下它的构成。

<?xml version='1.0' encoding='ISO-8859-1'?><?xml-stylesheet type='text/xsl' href='image_metadata_stylesheet.xsl'?><dataset><name>iBUG face point dataset - All images</name><comment>This folder contains data downloaded from:http://ibug.doc.ic.ac.uk/resources/facial-point-annotations/The dataset is actually a combination of the AFW, HELEN, iBUG, and LFPWface landmark datasets. But the iBUG people have aggregated it all togetherand gave them a consistent set of 68 landmarks across all the images, therebyturning it into one big dataset.Note that we have adjusted the coordinates of the points from the MATLAB conventionof 1 being the first index to 0 being the first index. So the coordinates in thisfile are in the normal C 0-indexed coordinate system.We have also added left right flips (i.e. mirrors) of each image and alsoappropriately flipped the landmarks. This doubles the size of the dataset.Each of the mirrored versions of the images has a filename that ends with_mirror.jpg.Finally, note that the bounding boxes are from dlib's default face detector. For thefaces the detector failed to detect, we guessed at what the bounding box would have beenhad the detector found it and used that.</comment><images> <image file='afw/1051618982_1.jpg'> <box top='206' left='469' width='216' height='216'> <part name='00' x='482' y='267'/> <part name='01' x='483' y='298'/> <part name='02' x='487' y='329'/> <part name='03' x='491' y='358'/> <part name='04' x='503' y='386'/> <part name='05' x='523' y='409'/> <part name='06' x='543' y='428'/> <part name='07' x='565' y='442'/> <part name='08' x='591' y='447'/> <part name='09' x='620' y='443'/> <part name='10' x='647' y='429'/> <part name='11' x='671' y='409'/> <part name='12' x='688' y='385'/> <part name='13' x='699' y='359'/> <part name='14' x='704' y='332'/> <part name='15' x='707' y='305'/> <part name='16' x='708' y='277'/> <part name='17' x='502' y='250'/> <part name='18' x='518' y='237'/> <part name='19' x='537' y='234'/> <part name='20' x='557' y='236'/> <part name='21' x='575' y='243'/> <part name='22' x='619' y='243'/> <part name='23' x='639' y='237'/> <part name='24' x='659' y='234'/> <part name='25' x='679' y='238'/> <part name='26' x='693' y='250'/> <part name='27' x='596' y='268'/> <part name='28' x='595' y='287'/> <part name='29' x='594' y='305'/> <part name='30' x='593' y='324'/> <part name='31' x='570' y='336'/> <part name='32' x='581' y='338'/> <part name='33' x='593' y='342'/> <part name='34' x='605' y='338'/> <part name='35' x='615' y='336'/> <part name='36' x='523' y='272'/> <part name='37' x='536' y='263'/> <part name='38' x='551' y='263'/> <part name='39' x='564' y='277'/> <part name='40' x='550' y='277'/> <part name='41' x='535' y='276'/> <part name='42' x='626' y='279'/> <part name='43' x='642' y='265'/> <part name='44' x='657' y='267'/> <part name='45' x='670' y='276'/> <part name='46' x='658' y='280'/> <part name='47' x='642' y='279'/> <part name='48' x='544' y='364'/> <part name='49' x='565' y='360'/> <part name='50' x='580' y='357'/> <part name='51' x='591' y='360'/> <part name='52' x='603' y='358'/> <part name='53' x='621' y='361'/> <part name='54' x='641' y='366'/> <part name='55' x='621' y='382'/> <part name='56' x='603' y='385'/> <part name='57' x='590' y='384'/> <part name='58' x='579' y='383'/> <part name='59' x='563' y='378'/> <part name='60' x='552' y='366'/> <part name='61' x='580' y='370'/> <part name='62' x='591' y='370'/> <part name='63' x='603' y='371'/> <part name='64' x='634' y='369'/> <part name='65' x='603' y='371'/> <part name='66' x='591' y='370'/> <part name='67' x='580' y='370'/> </box> </image> <image file='afw/111076519_1.jpg'> <box top='724' left='1122' width='150' height='150'> <part name='00' x='1126' y='765'/> <part name='01' x='1123' y='784'/> <part name='02' x='1123' y='804'/> <part name='03' x='1124' y='822'/> <part name='04' x='1131' y='839'/> <part name='05' x='1142' y='853'/> <part name='06' x='1157' y='865'/> <part name='07' x='1172' y='874'/> <part name='08' x='1190' y='878'/> <part name='09' x='1208' y='878'/> <part name='10' x='1225' y='873'/> <part name='11' x='1238' y='862'/> <part name='12' x='1249' y='846'/> <part name='13' x='1256' y='829'/> <part name='14' x='1261' y='810'/> <part name='15' x='1263' y='792'/> <part name='16' x='1264' y='774'/> <part name='17' x='1148' y='749'/> <part name='18' x='1160' y='745'/> <part name='19' x='1171' y='744'/> <part name='20' x='1183' y='748'/> <part name='21' x='1194' y='753'/> <part name='22' x='1227' y='756'/> <part name='23' x='1236' y='753'/> <part name='24' x='1244' y='753'/> <part name='25' x='1251' y='754'/> <part name='26' x='1256' y='759'/> <part name='27' x='1210' y='769'/> <part name='28' x='1210' y='779'/> <part name='29' x='1210' y='790'/> <part name='30' x='1209' y='800'/> <part name='31' x='1187' y='808'/> <part name='32' x='1196' y='811'/> <part name='33' x='1205' y='814'/> <part name='34' x='1212' y='813'/> <part name='35' x='1218' y='812'/> <part name='36' x='1159' y='766'/> <part name='37' x='1167' y='763'/> <part name='38' x='1176' y='764'/> <part name='39' x='1183' y='770'/> <part name='40' x='1175' y='770'/> <part name='41' x='1166' y='769'/> <part name='42' x='1225' y='776'/> <part name='43' x='1235' y='773'/> <part name='44' x='1243' y='774'/> <part name='45' x='1248' y='777'/> <part name='46' x='1241' y='779'/> <part name='47' x='1233' y='779'/> <part name='48' x='1160' y='825'/> <part name='49' x='1176' y='820'/> <part name='50' x='1190' y='822'/> <part name='51' x='1199' y='824'/> <part name='52' x='1209' y='825'/> <part name='53' x='1221' y='827'/> <part name='54' x='1229' y='833'/> <part name='55' x='1218' y='847'/> <part name='56' x='1205' y='852'/> <part name='57' x='1194' y='851'/> <part name='58' x='1184' y='849'/> <part name='59' x='1171' y='840'/> <part name='60' x='1165' y='827'/> <part name='61' x='1189' y='828'/> <part name='62' x='1199' y='830'/> <part name='63' x='1208' y='831'/> <part name='64' x='1225' y='834'/> <part name='65' x='1206' y='844'/> <part name='66' x='1196' y='844'/> <part name='67' x='1186' y='841'/> </box> </image> <image file='afw/111076519_2.jpg'> <box top='590' left='1028' width='180' height='180'> <part name='00' x='1050' y='620'/> <part name='01' x='1046' y='641'/> <part name='02' x='1040' y='663'/>

可以找到一些规律，按照这些规律来得到我们需要的数据，直接上代码：

void ReadLabelsFromFile(std::vector<ImageLabel> &Imagelabels, std::string Path = "labels_ibug_300W.xml"){ std::string ParentPath(trainFilePath); std::ifstream LabelsFile(ParentPath+Path, std::ios::in); if(!LabelsFile.is_open()) return; std::string linestr; while(std::getline(LabelsFile, linestr)){ linestr = trim(linestr); linestr = replace(linestr, "</", ""); linestr = replace(linestr, "/>", ""); linestr = replace(linestr, "<", ""); linestr = replace(linestr, ">", ""); linestr = replace(linestr, "'", ""); std::vector<std::string> strNodes = split(linestr, " "); static ImageLabel* mImageLabel = NULL; switch (strNodes.size()) { case 1: if(strNodes[0] == "image"){ Imagelabels.push_back(*mImageLabel); delete mImageLabel; } break; case 2: if(strNodes[0] == "image"){ mImageLabel = new ImageLabel(); mImageLabel->imagePath = ParentPath + split(strNodes[1], "=")[1];// std::cout << mImageLabel->imagePath << std::endl;// cv::Mat Image = cv::imread(mImageLabel->imagePath);// cv::imshow("Image", Image);// cv::waitKey(0); } break; case 5: if(strNodes[0] == "box"){ mImageLabel->faceBox[0] = atoi(split(strNodes[1], "=")[1].data()); mImageLabel->faceBox[1] = atoi(split(strNodes[2], "=")[1].data()); mImageLabel->faceBox[2] = atoi(split(strNodes[3], "=")[1].data()); mImageLabel->faceBox[3] = atoi(split(strNodes[4], "=")[1].data()); } break; case 4: if(strNodes[0] == "part"){ int index = atoi(split(strNodes[1], "=")[1].data()); mImageLabel->landmarkPos[index] = atoi(split(strNodes[2], "=")[1].data()); mImageLabel->landmarkPos[index+LandmarkPointsNum] = atoi(split(strNodes[3], "=")[1].data()); } break; default: break; } } LabelsFile.close();}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。