Question

有人可以帮助我吗？我想用一个数组填充一个数组，但我不知道如何因为我是这个java语言的新手。另外，我想学习如何编程的正确方法。提前致谢

import java.lang.*;
import java.io.*;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class ArffReader{
    public static void main(String[] args){
        BufferedReader reader = null;
        try{
            String CurrentLine;
            reader = new BufferedReader(new FileReader("weather.nominal.arff"));

                int counter = 0;
                while((CurrentLine = reader.readLine()) != null){
                    String[] SplitData = CurrentLine.split(" ");
                    //Get the relation
                    if(SplitData[0].equals("@relation")){
                    System.out.println(SplitData[1]);
                    }
                    System.out.println();

                        //Get the attribute
                        if(SplitData[0].equals("@attribute")){
                        System.out.println(SplitData[1]);                           
                        }

                    //}
                    counter++;
                }
        }catch(IOException e){
                e.printStackTrace();
        }finally{
            try{
                if(reader != null)reader.close();
            }catch(IOException ex){
                ex.printStackTrace();
            }
        }
    }
}

// Arff文件

@relation weather.symbolic 
@attribute outlook {sunny, overcast, rainy}
@attribute temperature {hot, mild, cool}
@attribute humidity {high, normal}
@attribute windy {TRUE, FALSE}
@attribute play {yes, no}

@data
sunny,hot,high,FALSE,no
sunny,hot,high,TRUE,no
overcast,hot,high,FALSE,yes
rainy,mild,high,FALSE,yes
rainy,cool,normal,FALSE,yes
rainy,cool,normal,TRUE,no
overcast,cool,normal,TRUE,yes
sunny,mild,high,FALSE,no
sunny,cool,normal,FALSE,yes
rainy,mild,normal,FALSE,yes
sunny,mild,normal,TRUE,yes
overcast,mild,high,TRUE,yes
overcast,hot,normal,FALSE,yes
rainy,mild,high,TRUE,no

//来自cmd的输出：

weather.symbolic


outlook

temperature

humidity

windy

play

//我更喜欢的输出：

weather.symbolic


outlook  temperature  humidity  windy  play

Answer 1

Instead of this 
System.out.println() ;
use System.out.print();

Answer 2

以下行（@attribute humidity {high，normal}）：

String[] SplitData = CurrentLine.split(" ");

会把它分解成一个String数组，如下所示：

SplitData[0] = "@attribute"
SplitData[1] = "humidity"
SplitData[2] = "{high,"
SplitData[3] = "normal}"

因此，如果您想打印湿度，只需打印它：

System.out.print(SplitData[1])

除非您想先将其分配给变量：

String tempData = SplitData[1];
System.out.print(tempData);

但不要将其分配给String数组。

String tempData[] = SplitData[1]; // ERROR!

因为那样你会有不匹配的类型。

Answer 3

所以你要做的就是在一行中打印属性。

只需使用System.out.print()代替System.out.println()。

Answer 4

此处，使用条件if进行打印并使用print()，在打印任何内容后都不提供换行符。

import java.lang.*;
import java.io.*;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class ArffReader{
    public static void main(String[] args){
        BufferedReader reader = null;
        try{
            String CurrentLine;
            reader = new BufferedReader(new FileReader("weather.nominal.arff"));

                int counter = 0;
                boolean check = false;
                while((CurrentLine = reader.readLine()) != null){
                    String[] SplitData = CurrentLine.split(" ");
                    //Get the relation
                    if(SplitData[0].equals("@relation")){
                    System.out.println(SplitData[1]);
                    System.out.println();
                    }
                        //Get the attribute
                        if(SplitData[0].equals("@attribute")){
                            if (check == false){
                                System.out.print(SplitData[1]); 
                            }else{
                                System.out.print(" "+SplitData[1]); 
                            }
                            check = true;

                        }
                    counter++;
                }
                System.out.println();
        }catch(IOException e){
                e.printStackTrace();
        }finally{
            try{
                if(reader != null)reader.close();
            }catch(IOException ex){
                ex.printStackTrace();
            }
        }
    }
}

存储一个数组以填充它并以单行打印

4 个答案: