如何从java中的文本文件中一次读取两个数字 [英] how to read two numbers at a time as input from a text file in java

问题描述

大家好，我只需要知道如何一次取两个数字作为文本文件的输入，因为我必须将这两个数字分配为i，j，以便我可以将它们与其他值进行比较

我的输入文件每行包含两个数字，用分隔，即

Hi guys, I just need to know how to take two numbers at a time as input from text file as i have to assign these two numbers as i,j so that i can compare them with other values
my input file contains two numbers per line separated with " " i.e,

1 2 
2 3 
4 5............. 

i几乎有1000双作为我的输入

这是到目前为止我的代码：

i nearly have 1000 pairs as my input
This is my code so far:

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class sample{
	public static void main(String args[]) throws FileNotFoundException
	{
		FileInputStream file = new FileInputStream("clusters.txt"); 
		Scanner inputFile = new Scanner(file);
                		while (inputFile.hasNextLine()) {

		String line = inputFile.nextLine( );
		System.out.println("line = '" + line + "'");
		final String[] array = line.split("\\s"); 
		System.out.println(Arrays.toString(array));
		int i = Integer.parseInt( array[0] );
		int j = Integer.parseInt( array[1] );
		System.out.println("i="+i+"j="+j);
	}
} }

我的问题是我能够打印i，j值但是我在这期间遇到了一些错误。我已编辑输出并仅发布错误部分

运行：

My problem is i am able to print the i,j values but i am getting some errors during this like.I have edited the output and posted only error parts
run:

i=33j=101
i=33j=103
i=33j=104
Exception in thread "main" java.lang.NumberFormatException: For input string: ""
i=34j=37
i=34j=45
i=34j=52
i=34j=57
i=34j=58
i=34j=64
i=34j=69
i=34j=70

	at java.lang.NumberFormatException.forInputString(i=41j=54
NumberFormatException.java:65)
i=41j=56
i=41j=58
i=41j=66
i=41j=70
i=41j=71
i=41j=78
	at java.lang.Integer.parseInt(i=41j=82
Integer.java:573i=41j=84
)
i=41j=85
i=41j=86
i=41j=87
i=41j=91
i=41j=92
i=41j=93
	at java.lang.Integer.parseInt(i=41j=94
Integer.java:596
i=41j=96
i=41j=106
)
i=41j=107
i=41j=108
i=41j=109
i=42j=44
i=42j=45
	at sample.main(sample.java:17)

推荐答案

在解析之前，请对每个数组元素执行以下步骤：



1.首先修剪它。

2.检查长度。如果大于零，那么解析否则不

Before parsing do the following steps with each array elements :

1. First trim it.
2. check the length. if greater zero then do the parsing otherwise not

这是一个示例代码希望它有帮助

使用 nextInt（）

this is a sample code hope it helps
use nextInt()

Scanner sc=new Scanner(new File("file location"));
int a,b,c;
a=sc.nextInt();
b=sc.nextInt();
System.out.println("a :"+a+" b:"+b);

从文本文件中读取，意味着您必须使用FileReader流。我建议您使用StreamTokenizer，它将FileReader流作为参数。通过使用此StreamTokenizer，您可以确定是否存在行尾（标记化器的TT_EOF方法）和空格。注意到空白区域将授予您检索数字的可能性。



您还可以使用方法nestToken（）来查找文件中的下一个字符。 />


祝你好运。

Reading from a text file, means that you must use a FileReader stream. I suggest that you use a StreamTokenizer, wich takes as argument the FileReader stream. And by using this StreamTokenizer, you can decide if there is a end of line( TT_EOF method for the tokenizer ) and a white space. Noticing the white space will grant you the posibillity of retrieving the numbers.

Also you can use the method nestToken() to find the next character in the file.

Best regards.

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