如何打印每行的第一个单词？

Question

I have a text file that reads like this:

1. Bananas that are not green
2. Pudding that is not vanilla
3. Soda that is not Pepsi
4. Bread that is not stale

I just want it to print out the first word of each line NOT INCLUDING NUMBERS!

It should print out as:

Bananas
Pudding    
Soda    
Bread

Here is my code:

public static void main(String[] args) {
    BufferedReader reader = null;
    ArrayList <String> myFileLines = new ArrayList <String>();

    try {
        String sCurrentLine;
        reader = new BufferedReader(new 
                FileReader("/Users/FakeUsername/Desktop/GroceryList.txt"));
        while ((sCurrentLine = reader.readLine()) != null) {
            System.out.println(sCurrentLine);               
        }
    } catch (IOException e) {
        e.printStackTrace();
        System.out.print(e.getMessage());
    } finally {
        try {
            if (reader != null)reader.close();
        } catch (IOException ex) {
            System.out.println(ex.getMessage());
            ex.printStackTrace();
        }
    }
}

Answer 1

Use the split function of String. It returns the array of the String as per the character which we want to split with the string. In your case, it is like as follow.

 String sCurrentLine = new String();
 reader = new BufferedReader(new 
                FileReader("/Users/FakeUsername/Desktop/GroceryList.txt"));
 while ((sCurrentLine = reader.readLine() != null) {
    String words[] = sCurrentLine.split(" ");
    System.out.println(words[0]+" "+words[1]);
 } 

Answer 2

Java 8+ you can use the BufferedReader 's lines() method to do this very easily:

String filename = "Your filename";
reader = new BufferedReader(new FileReader(fileName));
reader.lines()
      .map(line -> line.split("\\s+")[1])
      .forEach(System.out::println);

Output:

Bananas
Pudding
Soda
Bread

---

This will create a Stream of all the lines in the BufferedReader , split each line on whitespace, and then take the second token and print it

Answer 3

Please try the code below -:

outerWhileLoop: 
while ((sCurrentLine = reader.readLine()) != null) {
     //System.out.println(sCurrentLine);
     StringTokenizer st = new StringTokenizer(sCurrentLine," .");
     int cnt = 0;
     while (st.hasMoreTokens()){
        String temp = st.nextToken();
        cnt++;
        if (cnt == 2){
           System.out.println(temp);
           continue outerWhileLoop;  
        }
    }
}