Issues with regex in java

Question

I have started to learn regex since I have found it very usefull.

I have a task which I am trying to solve but my output fails. Read two files from keyboard, read first file and change all dots to exclamation marks and save the content of first file to second file. My solution:

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String file1 = reader.readLine();
        String file2 = reader.readLine();
        reader.close();

        FileReader fileReader = new FileReader(file1);
        FileWriter fileWriter = new FileWriter(file2);
        BufferedReader bufferedReader = new BufferedReader(fileReader);
        BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);

        String a;
        while ((a = bufferedReader.readLine()) != null) {
            a.replaceAll("\\.","\\!");
            bufferedWriter.write(a);
        }

        bufferedReader.close();
        bufferedWriter.close();
    }
}

`a = a.replace(".","!");` if you need to replace a dot with `!`, mind strings are immutable. — Wiktor Stribiżew, May 08 '20 at 11:18

score 0 · Answer 1 · edited May 08 '20 at 11:22

0

I don't think the backslashes are needed. Try just . and !.

edited May 08 '20 at 11:22

Wiktor Stribiżew

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answered May 08 '20 at 11:18

Paavo Rotstén

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It won't work in OP code. OP is using `.replaceAll` and if you remove the ``\`` before `.` it will match any char but line break chars. – Wiktor Stribiżew May 08 '20 at 11:22

Issues with regex in java

1 Answers1