CODEWITHSUNDEEP
java
user2408838
user2408838

Reputation: 21

how to determine if a String starts with a specific character?

Is there a built in method in Java to determine if a String starts with a specific character? How can I write, to an output file, only the lines that do not start with a defined character?

   try {
        File input = new File("input");
        File output = new File("output");
        Scanner sc = new Scanner(input);
        PrintWriter printer = new PrintWriter(output);
        while (sc.hasNextLine()) {
            String s = sc.nextLine();
            printer.write(s);
        }
        printer.flush();
    }
    catch (FileNotFoundException e) {
        System.err.println("File not found. Please scan in new file.");
    }

Upvotes: 2

Views: 4003

Answers (2)

Joetjah
Joetjah

Reputation: 6132

Built in a check if the character is there.

while (sc.hasNextLine()) {
    String s = sc.nextLine();
    if (s.startsWith("?"))
        printer.write(s);
}

Or

while (sc.hasNextLine()) {
    String s = sc.nextLine();
    char c = s.charAt(0);
    if (c.matches('?'))
        printer.write(s);
}

EDIT: Based on your comment:

int i;
char c;
String s;
while (sc.hasNextLine()) {
    s = sc.nextLine();
    c = ' ';
    i = 0;
    while (c.matches(' ')) {
        c = s.charAt(i);
        if (c.matches('?'))
            printer.write(s);
        i++;
    }
}

Not sure if the code works, I'm currently unable to test the code. But you might get the idea.

Upvotes: 1

Lokesh
Lokesh

Reputation: 7940

You can easily check for text before writing in your while loop.

 if(check your string)
   printer.write(s);

Upvotes: 0

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