CODEWITHSUNDEEP
javaparsing
Manas
Manas

Reputation: 1

Java Input through formatted file

I need to take input from the file of the format

2 (3,4) (5,6) 3 (6,5) (7,8)

where I want just the integer value to store in some variable ,I dont want brackets and commas so how do I get this using pattern-match?

Upvotes: 0

Views: 71

Answers (3)

Robert Salthouse
Robert Salthouse

Reputation: 11

I prefer the String method split, which allows use of regular expressions. Here's some example code to run for each line of input from your file, assuming you have instantiated an instance variable named contents of type ArrayList<Integer>:

public void readLine(String line) {
    String delimiters = "[ ,()]+"; // regular expression
    String[] tokens = line.split(delimiters);
    for (String token : tokens) {
        try {
            Integer i = Integer.parseInt(token); // convert String to Integer
            contents.add(i);
        } catch (NumberFormatException e) {
            // TODO: handle exception
        }
    }
}

The split method creates a few extra (empty) tokens, which the try/catch eliminates. Hope this helps.

Upvotes: 1

hmjd
hmjd

Reputation: 121971

You can read the integers directly from the file using java.util.Scanner and specify a delimiter using Scanner.useDelimiter(Pattern), where the delimiter would be a regular expression ("[,() ]{1,}" for example). The Scanner methods hasNextInt() and nextInt() can be used to read the integers.

Upvotes: 0

The Cat
The Cat

Reputation: 2475

You can use String#replaceAll("[^0-9]", "") to remove any non-numeric characters and Integer.valueOf(String) to get an Integer.

Upvotes: 0

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