CODEWITHSUNDEEP
javastringfor-looparraylistinteger
FyreeW
FyreeW

Reputation: 415

Getting a Syntax error when trying to use a method using ArrayLists?

So right now I am getting an Syntax error when I am trying to use a method that does not return any value (is void), and that takes in arguments ArrayList<E> fileList. My goal is to take in a text file that has both String, and Integer objects, and in the remove method if it finds a Integer then it will be removed from the list. This is so it will only be leaving the Strings at the end. Here is the code that shows both the reading of the file, and the removeInts method I am trying to use:

@SuppressWarnings("unchecked") //IDE told me to add this for adding objects to the ArrayList
public <E> ArrayList<E> readFile(){
    ArrayList<E> fileList = new ArrayList<E>();
    try {
        Scanner read = new Scanner(file); //would not let me do this without error handling
        while(read.hasNext()){ //while there is still stuff to add it will keep filling up the ArrayList
            fileList.add((E)read.next());
        }
    } catch (FileNotFoundException e) {
        System.out.println("File not found!");
        e.printStackTrace();
    }
    removeInts(fileList);
    return fileList;    
}

public void removeInts(ArrayList<E> fileList){
    for(int i = 0; i < fileList.size(); i++){
        if(fileList.get(i) instanceof Integer){
            fileList.remove(i);
        }
        else{
            //does nothing, does not remove the object if it is a string
        }
    }

I am getting the syntax error at removeInts(fileList).

Upvotes: 0

Views: 58

Answers (2)

Andreas
Andreas

Reputation: 159135

As others pointed out, your list will never contain an Integer, because next() returns a String.

Given your last comment:

I am trying to be able to remove ints from a text file, only leaving strings left. Say for example I had a text file that said "A B C 1 2 3", first the Scanner (I need to use a scanner) would take in the file, and put it into an ArrayList. Then when I use the remove method it would take out all values that are Integers, and leave alone the Strings. The final output at the end would be "A B C".

Don't first load them as Integer and then remove them. Instead, don't load them:

List<String> list = new ArrayList<>();
try (Scanner sc = new Scanner("A B C 1 2 3")) {
    while (sc.hasNext()) {
        if (sc.hasNextInt())
            sc.nextInt(); // get and discard
        else
            list.add(sc.next());
    }
}
System.out.println(list);

Output

[A, B, C]

Upvotes: 3

James Wierzba
James Wierzba

Reputation: 17548

Change the signature of removeInts to be generic:

public <E> void removeInts(ArrayList<E> fileList)

Upvotes: 2

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