如何实现换行显示def getActors(filename): actors = dict() # 打开xlsx文件，并获取第一个worksheet wb = openpyxl.load_workbook((filename)) ws = wb.worksheets[0] # 遍历Excel文件中的所有文件中的所有行 for index, row in enumerate(ws.rows): # 跳过第一行的表头 if index == 0: continue # 获取电影名称和演员列表 fileName, actor = row[0].value, row[1].value.split('/') # 遍历该电影所有演员，统计参演电影 for a in actor: actors[a] = actors.get(a, set()) actors[a].add(fileName) return actors data = getActors('实践2素材.xlsx') print(data)

您可以在每个 print 语句后面添加换行符 "\n" 来实现换行输出。例如，您可以这样写：

def getActors(filename):
    actors = dict()
    # 打开xlsx文件，并获取第一个worksheet
    wb = openpyxl.load_workbook((filename))
    ws = wb.worksheets[0]
    # 遍历Excel文件中的所有文件中的所有行
    for index, row in enumerate(ws.rows):
        # 跳过第一行的表头
        if index == 0:
            continue
        # 获取电影名称和演员列表
        fileName, actor = row[0].value, row[1].value.split('/')
        # 遍历该电影所有演员，统计参演电影
        for a in actor:
            actors[a] = actors.get(a, set())
            actors[a].add(fileName)
    return actors

data = getActors('实践2素材.xlsx')
print(data, "\n")

这样每次执行完 `print(data)` 后，会自动换行，使得下一行的输出与上一行的输出分开来，更加清晰易读。

相关问题

在cloudcompare的mainwindow.cpp中，用C++定义一个函数void MainWindow::DBH()，基于最小二乘法，通过获取当前选中的实体作为点云文件来源，实现对txt格式的树木点云文件的胸径计算

可以参考以下代码实现：

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <cmath>

#include <QFileDialog>
#include <QMessageBox>

#include <pcl/point_types.h>
#include <pcl/io/pcd_io.h>
#include <pcl/visualization/pcl_visualizer.h>

typedef pcl::PointXYZ PointT;
typedef pcl::PointCloud<PointT> PointCloudT;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    //连接信号与槽函数
    connect(ui->actionOpen, SIGNAL(triggered(bool)), this, SLOT(openFile()));
    connect(ui->pushButton, SIGNAL(clicked(bool)), this, SLOT(DBH()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::openFile()
{
    QString fileName = QFileDialog::getOpenFileName(this, tr("Open Point Cloud"), "", tr("Point Cloud Files (*.pcd *.txt)"));

    if(!fileName.isEmpty())
    {
        //清空界面
        ui->qvtkWidget->update();
        ui->textBrowser->clear();

        //读取点云文件
        pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
        if (pcl::io::loadPCDFile<pcl::PointXYZ>(fileName.toStdString(), *cloud) == -1)
        {
            //尝试读取txt格式文件
            std::ifstream ifs(fileName.toStdString());
            if (!ifs.is_open())
            {
                QMessageBox::critical(this, "Error", "Cannot open file!");
                return;
            }

            std::string line;
            while (std::getline(ifs, line))
            {
                pcl::PointXYZ p;
                std::stringstream ss(line);
                ss >> p.x >> p.y >> p.z;
                cloud->push_back(p);
            }

            ifs.close();
        }

        //显示点云
        pcl::visualization::PCLVisualizer vis("Point Cloud");
        vis.setBackgroundColor(0.0, 0.0, 0.0);
        vis.addPointCloud(cloud, "cloud");
        vis.setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 1, "cloud");
        ui->qvtkWidget->update();

        //输出点云信息
        std::stringstream ss;
        ss << "Number of points: " << cloud->size() << std::endl;
        ui->textBrowser->append(ss.str().c_str());

        //保存点云
        cloud_ = cloud;
    }
}

void MainWindow::DBH()
{
    if (!cloud_)
    {
        QMessageBox::warning(this, "Warning", "No point cloud selected!");
        return;
    }

    //获取选中的点
    std::vector<int> indices;
    if (ui->qvtkWidget->getRenderWindow()->GetRenderers()->GetFirstRenderer()->GetViewProp("cloud"))
    {
        vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
        actor = ui->qvtkWidget->getRenderWindow()->GetRenderers()->GetFirstRenderer()->GetActors()->GetLastActor();
        vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
        mapper = vtkPolyDataMapper::SafeDownCast(actor->GetMapper());
        vtkSmartPointer<vtkDataSet> dataSet = vtkSmartPointer<vtkDataSet>::New();
        dataSet = mapper->GetInput();
        vtkSmartPointer<vtkUnsignedCharArray> pointColors = vtkSmartPointer<vtkUnsignedCharArray>::New();
        pointColors = vtkUnsignedCharArray::SafeDownCast(dataSet->GetPointData()->GetScalars());
        for (vtkIdType i = 0; i < pointColors->GetNumberOfTuples(); i++)
        {
            if (pointColors->GetValue(i) == 255)
            {
                indices.push_back(i);
            }
        }
    }

    if (indices.empty())
    {
        QMessageBox::warning(this, "Warning", "No point selected!");
        return;
    }

    //计算胸径
    double sum_x = 0.0, sum_y = 0.0, sum_z = 0.0, sum_xy = 0.0, sum_xz = 0.0, sum_xx = 0.0;
    for (int i : indices)
    {
        sum_x += cloud_->points[i].x;
        sum_y += cloud_->points[i].y;
        sum_z += cloud_->points[i].z;
        sum_xx += cloud_->points[i].x * cloud_->points[i].x;
        sum_xy += cloud_->points[i].x * cloud_->points[i].y;
        sum_xz += cloud_->points[i].x * cloud_->points[i].z;
    }

    double n = static_cast<double>(indices.size());
    double a = (n * sum_xy - sum_x * sum_y) / (n * sum_xx - sum_x * sum_x);
    double b = (sum_y - a * sum_x) / n;
    double c = (n * sum_xz - sum_x * sum_z) / (n * sum_xx - sum_x * sum_x);
    double d = (sum_z - c * sum_x) / n;
    double D = 2.0 * sqrt(a * a + 1) * 1000.0; //单位：毫米

    //输出胸径
    std::stringstream ss;
    ss << "DBH: " << D << " mm" << std::endl;
    ui->textBrowser->append(ss.str().c_str());
}

该函数基于最小二乘法，通过获取当前选中的实体作为点云文件来源，实现对txt格式的树木点云文件的胸径计算。

android ListView写一个电影列表

以下是一个简单的电影列表示例，其中包含电影名称、导演和演员列表：

1. 创建一个新的Android项目，然后在布局文件中添加一个ListView组件：

<ListView
    android:id="@+id/movie_list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

2. 在Activity中获取ListView组件的引用，并创建一个Movie类作为数据模型：

public class Movie {
    private String title;
    private String director;
    private List<String> actors;

    public Movie(String title, String director, List<String> actors) {
        this.title = title;
        this.director = director;
        this.actors = actors;
    }

    public String getTitle() {
        return title;
    }

    public String getDirector() {
        return director;
    }

    public List<String> getActors() {
        return actors;
    }
}

public class MainActivity extends AppCompatActivity {
    private ListView movieList;
    private List<Movie> movies;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        movieList = findViewById(R.id.movie_list);

        movies = new ArrayList<>();
        movies.add(new Movie("The Shawshank Redemption", "Frank Darabont", Arrays.asList("Tim Robbins", "Morgan Freeman")));
        movies.add(new Movie("The Godfather", "Francis Ford Coppola", Arrays.asList("Marlon Brando", "Al Pacino", "James Caan")));
        movies.add(new Movie("The Dark Knight", "Christopher Nolan", Arrays.asList("Christian Bale", "Heath Ledger", "Aaron Eckhart")));

        MovieAdapter adapter = new MovieAdapter(this, movies);
        movieList.setAdapter(adapter);
    }
}

3. 创建一个自定义适配器MovieAdapter，用于将Movie对象显示在ListView中：

public class MovieAdapter extends ArrayAdapter<Movie> {
    private Context context;
    private List<Movie> movies;

    public MovieAdapter(Context context, List<Movie> movies) {
        super(context, R.layout.movie_item, movies);
        this.context = context;
        this.movies = movies;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            LayoutInflater inflater = LayoutInflater.from(context);
            convertView = inflater.inflate(R.layout.movie_item, parent, false);
        }

        TextView titleView = convertView.findViewById(R.id.title);
        TextView directorView = convertView.findViewById(R.id.director);
        TextView actorsView = convertView.findViewById(R.id.actors);

        Movie movie = movies.get(position);

        titleView.setText(movie.getTitle());
        directorView.setText("Director: " + movie.getDirector());
        actorsView.setText("Actors: " + TextUtils.join(", ", movie.getActors()));

        return convertView;
    }
}

4. 创建一个布局文件movie_item.xml，用于定义ListView中每个电影项的布局：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="16dp">

    <TextView
        android:id="@+id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:textStyle="bold"/>

    <TextView
        android:id="@+id/director"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <TextView
        android:id="@+id/actors"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

5. 运行应用程序，您应该会看到一个电影列表，其中包含上面定义的电影。

这只是一个简单的示例，您可以根据需要更改布局和数据模型来创建更复杂的电影列表。