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Swift：将数组作为值过滤字典(Swift: Filter a Dictionary with Array as Value)

 我是Swift编程的新手。 对于我的特定项目，我试图用一些用户输入过滤字典，字典的值由一个数组组成。  
 以下是一些示例代码，以及我想要实现的内容：  
var dictionary = ["a": ["aberration", "abc"], "b" : ["babel", "bereft"]]

var filteredDictionary = [String: [String]]()

var searchText = "aberration"

//getting the first letter of string
var firstLetter = searchText[searchText.startIndex]
 
 有了这个特定的searchText，我试图得到：  
filteredDictionary = ["a": ["aberration"]]
 
 编辑：我想让字典返回第一个字母作为其关键字，以及与searchText匹配的值。 对不起，如果我不清楚。  
 以下是我尝试过的一些代码，但很明显，我无法使其工作：  
filteredDictionary = dictionary.filter{$0.key == firstLetter && for element in $0.value { element.hasPrefix(searchText) }}
 
 任何帮助，将不胜感激。 谢谢。 

I'm new to Swift programming. For my particular project, I'm trying to filter a dictionary with some user input, and the dictionary's value consists of an array. 
Here is some sample code, and what I'm trying to accomplish: 
var dictionary = ["a": ["aberration", "abc"], "b" : ["babel", "bereft"]]

var filteredDictionary = [String: [String]]()

var searchText = "aberration"

//getting the first letter of string
var firstLetter = searchText[searchText.startIndex]
 
With this particular searchText, I'm trying to get: 
filteredDictionary = ["a": ["aberration"]]
 
Edit: I want the dictionary to return with the first letter as its key, and the values with what searchText matches up with. Sorry if it I wasn't clear. 
Here is some code I have tried, but obviously, I can't get it to work:  
filteredDictionary = dictionary.filter{$0.key == firstLetter && for element in $0.value { element.hasPrefix(searchText) }}
 
Any help would be appreciated. Thanks.

原文：https://stackoverflow.com/questions/48089253

更新时间：2023-08-09 21:08

最满意答案

 基于JewelSea在AnimatedAreaChart上的例子，我修改了它，以基于LineGraph为您制作一个类似的例子。 请看一下这个例子，希望它满足您的需求！  
import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.stage.Stage;

import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;


public class AnimatedLineChart extends Application {

    private static final int MAX_DATA_POINTS = 50;
    private int xSeriesData = 0;
    private XYChart.Series<Number, Number> series1 = new XYChart.Series<>();
    private XYChart.Series<Number, Number> series2 = new XYChart.Series<>();
    private XYChart.Series<Number, Number> series3 = new XYChart.Series<>();
    private ExecutorService executor;
    private ConcurrentLinkedQueue<Number> dataQ1 = new ConcurrentLinkedQueue<>();
    private ConcurrentLinkedQueue<Number> dataQ2 = new ConcurrentLinkedQueue<>();
    private ConcurrentLinkedQueue<Number> dataQ3 = new ConcurrentLinkedQueue<>();

    private NumberAxis xAxis;

    private void init(Stage primaryStage) {

        xAxis = new NumberAxis(0, MAX_DATA_POINTS, MAX_DATA_POINTS / 10);
        xAxis.setForceZeroInRange(false);
        xAxis.setAutoRanging(false);
        xAxis.setTickLabelsVisible(false);
        xAxis.setTickMarkVisible(false);
        xAxis.setMinorTickVisible(false);

        NumberAxis yAxis = new NumberAxis();

        // Create a LineChart
        final LineChart<Number, Number> lineChart = new LineChart<Number, Number>(xAxis, yAxis) {
            // Override to remove symbols on each data point
            @Override
            protected void dataItemAdded(Series<Number, Number> series, int itemIndex, Data<Number, Number> item) {
            }
        };

        lineChart.setAnimated(false);
        lineChart.setTitle("Animated Line Chart");
        lineChart.setHorizontalGridLinesVisible(true);

        // Set Name for Series
        series1.setName("Series 1");
        series2.setName("Series 2");
        series3.setName("Series 3");

        // Add Chart Series
        lineChart.getData().addAll(series1, series2, series3);

        primaryStage.setScene(new Scene(lineChart));
    }


    @Override
    public void start(Stage stage) {
        stage.setTitle("Animated Line Chart Sample");
        init(stage);
        stage.show();


        executor = Executors.newCachedThreadPool(new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread thread = new Thread(r);
                thread.setDaemon(true);
                return thread;
            }
        });

        AddToQueue addToQueue = new AddToQueue();
        executor.execute(addToQueue);
        //-- Prepare Timeline
        prepareTimeline();
    }

    private class AddToQueue implements Runnable {
        public void run() {
            try {
                // add a item of random data to queue
                dataQ1.add(Math.random());
                dataQ2.add(Math.random());
                dataQ3.add(Math.random());

                Thread.sleep(500);
                executor.execute(this);
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }
    }

    //-- Timeline gets called in the JavaFX Main thread
    private void prepareTimeline() {
        // Every frame to take any data from queue and add to chart
        new AnimationTimer() {
            @Override
            public void handle(long now) {
                addDataToSeries();
            }
        }.start();
    }

    private void addDataToSeries() {
        for (int i = 0; i < 20; i++) { //-- add 20 numbers to the plot+
            if (dataQ1.isEmpty()) break;
            series1.getData().add(new XYChart.Data<>(xSeriesData++, dataQ1.remove()));
            series2.getData().add(new XYChart.Data<>(xSeriesData++, dataQ2.remove()));
            series3.getData().add(new XYChart.Data<>(xSeriesData++, dataQ3.remove()));
        }
        // remove points to keep us at no more than MAX_DATA_POINTS
        if (series1.getData().size() > MAX_DATA_POINTS) {
            series1.getData().remove(0, series1.getData().size() - MAX_DATA_POINTS);
        }
        if (series2.getData().size() > MAX_DATA_POINTS) {
            series2.getData().remove(0, series2.getData().size() - MAX_DATA_POINTS);
        }
        if (series3.getData().size() > MAX_DATA_POINTS) {
            series3.getData().remove(0, series3.getData().size() - MAX_DATA_POINTS);
        }
        // update
        xAxis.setLowerBound(xSeriesData - MAX_DATA_POINTS);
        xAxis.setUpperBound(xSeriesData - 1);
    }

    public static void main(String[] args) {
        launch(args);
    }
}
 
 NB我没有照顾更新X轴上的值，你可以这样做！ 

Based on JewelSea's example on AnimatedAreaChart, I modified it to make a similar example for you based on LineGraph. Please have a look at the example, hope it satisfies your need! 
import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.stage.Stage;

import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;


public class AnimatedLineChart extends Application {

    private static final int MAX_DATA_POINTS = 50;
    private int xSeriesData = 0;
    private XYChart.Series<Number, Number> series1 = new XYChart.Series<>();
    private XYChart.Series<Number, Number> series2 = new XYChart.Series<>();
    private XYChart.Series<Number, Number> series3 = new XYChart.Series<>();
    private ExecutorService executor;
    private ConcurrentLinkedQueue<Number> dataQ1 = new ConcurrentLinkedQueue<>();
    private ConcurrentLinkedQueue<Number> dataQ2 = new ConcurrentLinkedQueue<>();
    private ConcurrentLinkedQueue<Number> dataQ3 = new ConcurrentLinkedQueue<>();

    private NumberAxis xAxis;

    private void init(Stage primaryStage) {

        xAxis = new NumberAxis(0, MAX_DATA_POINTS, MAX_DATA_POINTS / 10);
        xAxis.setForceZeroInRange(false);
        xAxis.setAutoRanging(false);
        xAxis.setTickLabelsVisible(false);
        xAxis.setTickMarkVisible(false);
        xAxis.setMinorTickVisible(false);

        NumberAxis yAxis = new NumberAxis();

        // Create a LineChart
        final LineChart<Number, Number> lineChart = new LineChart<Number, Number>(xAxis, yAxis) {
            // Override to remove symbols on each data point
            @Override
            protected void dataItemAdded(Series<Number, Number> series, int itemIndex, Data<Number, Number> item) {
            }
        };

        lineChart.setAnimated(false);
        lineChart.setTitle("Animated Line Chart");
        lineChart.setHorizontalGridLinesVisible(true);

        // Set Name for Series
        series1.setName("Series 1");
        series2.setName("Series 2");
        series3.setName("Series 3");

        // Add Chart Series
        lineChart.getData().addAll(series1, series2, series3);

        primaryStage.setScene(new Scene(lineChart));
    }


    @Override
    public void start(Stage stage) {
        stage.setTitle("Animated Line Chart Sample");
        init(stage);
        stage.show();


        executor = Executors.newCachedThreadPool(new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread thread = new Thread(r);
                thread.setDaemon(true);
                return thread;
            }
        });

        AddToQueue addToQueue = new AddToQueue();
        executor.execute(addToQueue);
        //-- Prepare Timeline
        prepareTimeline();
    }

    private class AddToQueue implements Runnable {
        public void run() {
            try {
                // add a item of random data to queue
                dataQ1.add(Math.random());
                dataQ2.add(Math.random());
                dataQ3.add(Math.random());

                Thread.sleep(500);
                executor.execute(this);
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }
    }

    //-- Timeline gets called in the JavaFX Main thread
    private void prepareTimeline() {
        // Every frame to take any data from queue and add to chart
        new AnimationTimer() {
            @Override
            public void handle(long now) {
                addDataToSeries();
            }
        }.start();
    }

    private void addDataToSeries() {
        for (int i = 0; i < 20; i++) { //-- add 20 numbers to the plot+
            if (dataQ1.isEmpty()) break;
            series1.getData().add(new XYChart.Data<>(xSeriesData++, dataQ1.remove()));
            series2.getData().add(new XYChart.Data<>(xSeriesData++, dataQ2.remove()));
            series3.getData().add(new XYChart.Data<>(xSeriesData++, dataQ3.remove()));
        }
        // remove points to keep us at no more than MAX_DATA_POINTS
        if (series1.getData().size() > MAX_DATA_POINTS) {
            series1.getData().remove(0, series1.getData().size() - MAX_DATA_POINTS);
        }
        if (series2.getData().size() > MAX_DATA_POINTS) {
            series2.getData().remove(0, series2.getData().size() - MAX_DATA_POINTS);
        }
        if (series3.getData().size() > MAX_DATA_POINTS) {
            series3.getData().remove(0, series3.getData().size() - MAX_DATA_POINTS);
        }
        // update
        xAxis.setLowerBound(xSeriesData - MAX_DATA_POINTS);
        xAxis.setUpperBound(xSeriesData - 1);
    }

    public static void main(String[] args) {
        launch(args);
    }
}
 
N.B. I haven't taken care of updating the values on the X-axis, you can do that !

Swift：将数组作为值过滤字典(Swift: Filter a Dictionary with Array as Value)

最满意答案

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