Read the first word of each line of a text file into an ArrayList

Question

I have a long local text file and I would like to write a method that will read it and add the first word of each line into an ArrayList of Strings .

I have a very primitive understanding of basic I/O operations. Right now, from what I understand, I would need to have some kind of InputReader object read each first word and then use something like an OutputStreamBuffer to add each of those words as Strings to the ArrayList in turn. Am I on the right track?

If that is correct, I'm not exactly sure what the correct syntax would be to do it (especially with having the InputStreamReader go to the next line after copying the first word in each line. If I'm not even close, what would you guys do?

Thanks a lot for your help everyone. I hope my description was clear enough for you.

Answer 1

You're on the right track - here's my general suggestion for your requirement...

1. Create an ArrayList<String> for storing your words
2. Use a BufferedReader to read from your file line-by-line using readLine();
3. Split the line up and read the first word only (maybe use the String.split() method or a StringTokenizer or a regex expression)
4. Store the word in the ArrayList using an add() method and then read the next line from point 2.

There shouldn't be a need to use an OutputStream for your ArrayList , thats just complicating things.

Answer 2

I'd use java.util.Scanner , specifically the hasNextLine and nextLine methods to get each line.

Then use another scanner on each line and the hasNext and next methods to get the first word, or use the String split method (or some other way) to get the first word.

Then add the first word into the ArrayList<String> .