7

我知道如何Java使用 usingScanner和 File IOException 读取文件，但我唯一不知道的是如何将文件中的文本作为数组存储。

这是snippet我的一段代码：

 public static void main(String[] args) throws IOException{
    // TODO code application logic here

    // // read KeyWestTemp.txt

    // create token1
    String token1 = "";

    // for-each loop for calculating heat index of May - October


    // create Scanner inFile1
    Scanner inFile1 = new Scanner(new File("KeyWestTemp.txt"));

    // while loop
    while(inFile1.hasNext()){

        // how can I create array from text read?

        // find next line
        token1 = inFile1.nextLine();

这是我的KeyWestTemp.txt文件包含的内容：

70.3,   70.8,   73.8,   77.0,   80.7,   83.4,   84.5,   84.4,   83.4,   80.2,   76.3,   72.0
4

7 回答 7

16

存储为字符串：

public class ReadTemps {

    public static void main(String[] args) throws IOException {
    // TODO code application logic here

    // // read KeyWestTemp.txt

    // create token1
    String token1 = "";

    // for-each loop for calculating heat index of May - October

    // create Scanner inFile1
    Scanner inFile1 = new Scanner(new File("KeyWestTemp.txt")).useDelimiter(",\\s*");

    // Original answer used LinkedList, but probably preferable to use ArrayList in most cases
    // List<String> temps = new LinkedList<String>();
    List<String> temps = new ArrayList<String>();

    // while loop
    while (inFile1.hasNext()) {
      // find next line
      token1 = inFile1.next();
      temps.add(token1);
    }
    inFile1.close();

    String[] tempsArray = temps.toArray(new String[0]);

    for (String s : tempsArray) {
      System.out.println(s);
    }
  }
}

对于花车：

import java.io.File;
import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;

public class ReadTemps {

  public static void main(String[] args) throws IOException {
    // TODO code application logic here

    // // read KeyWestTemp.txt

    // create token1

    // for-each loop for calculating heat index of May - October

    // create Scanner inFile1
    Scanner inFile1 = new Scanner(new File("KeyWestTemp.txt")).useDelimiter(",\\s*");


    // Original answer used LinkedList, but probably preferable to use ArrayList in most cases
    // List<Float> temps = new LinkedList<Float>();
    List<Float> temps = new ArrayList<Float>();

    // while loop
    while (inFile1.hasNext()) {
      // find next line
      float token1 = inFile1.nextFloat();
      temps.add(token1);
    }
    inFile1.close();

    Float[] tempsArray = temps.toArray(new Float[0]);

    for (Float s : tempsArray) {
      System.out.println(s);
    }
  }
}
于 2013-11-07T19:30:50.377 回答
2

只需将整个文件读入 StringBuilder，然后在空格后按点分割字符串。你会得到一个字符串数组。

Scanner inFile1 = new Scanner(new File("KeyWestTemp.txt"));

StringBuilder sb = new StringBuilder();
while(inFile1.hasNext()) {
    sb.append(inFile1.nextLine());
}

String[] yourArray = sb.toString().split(", ");
于 2013-11-07T19:20:40.570 回答
2

如果您不知道文件中的行数，那么您就没有用于初始化数组的大小。在这种情况下，使用 List 更有意义：

List<String> tokens = new ArrayList<String>();
while (inFile1.hasNext()) {
    tokens.add(inFile1.nextLine());
}

之后，如果需要，可以复制到数组：

String[] tokenArray = tokens.toArray(new String[0]);
于 2013-11-07T19:21:18.910 回答
1 
while(inFile1.hasNext()){

    token1 = inFile1.nextLine();

    // put each value into an array with String#split();
    String[] numStrings = line.split(", ");

    // parse number string into doubles 
    double[] nums = new double[numString.length];

    for (int i = 0; i < nums.length; i++){
        nums[i] = Double.parseDouble(numStrings[i]);
    }

}
于 2013-11-07T19:19:47.033 回答
0

我发现这种从文件中读取字符串的方式最适合我

String st, full;
full="";
BufferedReader br = new BufferedReader(new FileReader(URL));
while ((st=br.readLine())!=null) {
    full+=st;
}

“full”将是所有行的完整组合。如果您想在文本行之间添加换行符，您会这样做 full+=st+"\n";

于 2013-11-07T19:29:26.680 回答
0 
int count = -1;
String[] content = new String[200];
while(inFile1.hasNext()){

    content[++count] = inFile1.nextLine();
}

编辑

看起来你想创建一个浮点数组，为此创建一个浮点数组

int count = -1;
Float[] content = new Float[200];
while(inFile1.hasNext()){

    content[++count] = Float.parseFloat(inFile1.nextLine());
}

那么你的浮点数组看起来像

content[0] = 70.3
content[1] = 70.8
content[2] = 73.8
content[3] = 77.0 and so on
于 2013-11-07T19:16:55.220 回答
0

我使用这种方法：

import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;

public class TEST {
    static Scanner scn;

public static void main(String[] args) {
    String text = "";

    try{
        scn = new Scanner(new File("test.txt"));
    }catch(FileNotFoundException ex){System.out.println(ex.getMessage());}
    while(scn.hasNext()){
        text += scn.next();
        }
        String[] arry = text.split(",");

    //if need converting to float do this:
    Float[] arrdy = new Float[arry.length];
    for(int i = 0; i < arry.length; i++){
            arrdy[i] = Float.parseFloat(arry[i]);
        }
    System.out.println(Arrays.toString(arrdy));
            }
}
于 2017-03-01T22:01:23.910 回答