how to skip a character when read strings from a file in Java

Question

For example, the content of a file is:

black=white

bad=good

easy=hard

So, I want to store in a map this words as key and value (ex: {black=white, bad=good} ). And my problem is when I read string I have to skip a char '=' which disappears key and value. How to make this?

In code below I make a code which read key and value from file, but this code works just when between words is SPACE, but I have to be '='.

System.out.println("File name:");
    String pathToFile = in.nextLine();
    File cardFile = new File(pathToFile);
    try(Scanner scanner = new Scanner(cardFile)){
        while(scanner.hasNext()) {
            key = scanner.next();
            value = scanner.next();
            flashCards.put(key, value);
        }
    }catch (FileNotFoundException e){
        System.out.println("No file found: " + pathToFile);
    }

What about reading a whole line at a time and splitting it with "=" character? — Amongalen
– Amongalen, Commented Jul 22, 2020 at 6:32

MC Emperor · Accepted Answer · 2020-07-22 07:28:42Z

3

Use the split method of String in Java.

so after reading your line, split the string and take the key and value as so.

String[] keyVal = line.split("=");
System.out.println("key is ", keyVal[0]);
System.out.println("value is ", keyVal[1]);

edited Jul 22, 2020 at 7:28

MC Emperor

23.3k16 gold badges90 silver badges139 bronze badges

answered Jul 22, 2020 at 6:34

maha

6435 silver badges20 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

matt · Accepted Answer · 2020-07-22 06:59:28Z

1

You can change the delimiter for the scanner.

public static void main (String[] args) throws java.lang.Exception
{
    String s = "black=white\nbad=good\neasy=hard";
    Scanner scan = new Scanner(s);
    scan.useDelimiter("\\n+|=");
    while(scan.hasNext()){
        
        String key = scan.next();
        String value = scan.next();
        System.out.println(key + ", " + value);
    }
}

The output:

black, white
bad, good
easy, hard

Changing the delimiter can be tricky, and it could be better to just read each line,then parse it. For example, "\\n+|=" will split the tokens by either one or more endlines, or an "=". The end line is somewhat hard coded though so it could change depending on the platform the file was created on.

edited Jul 22, 2020 at 6:59

answered Jul 22, 2020 at 6:54

matt

12.4k3 gold badges28 silver badges44 bronze badges

Comments

Juno · Accepted Answer · 2020-07-22 06:38:59Z

-1

A simple "if" condition will solve it.

if (key == '='){ break;}

answered Jul 22, 2020 at 6:38

Juno

816 bronze badges

Collectives™ on Stack Overflow

how to skip a character when read strings from a file in Java

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related