Cách sử dụng đối tượng String

Trong post này:

  • Lấy độ dài String
  • So sánh String
  • Conver String thành Characters
  • Tìm kiếm trong String
  • Tìm vi trí xâu trong String
  • Cắt String
  • Convert String
  • Replacing xâu trong String
  • Swtich String
  • Switch Compare String

1. Lấy độ dài String

public class Main {
  public static void main(String[] args) {
    String str1 = new String();
    String str2 = new String("Hello");
    int len1 = str1.length();
    int len2 = str2.length();

    // Display the length of str1 and str2
    System.out.println("Length of \"" + str1 + "\" = " + len1);
    System.out.println("Length of \"" + str2 + "\" = " + len2);
  }
}

2. So sánh String

public class Main {
  public static void main(String[] args) {
    String apple = new String("Apple");
    String orange = new String("Orange");
    System.out.println(apple.equals(orange));
    System.out.println(apple.equals(apple));
    System.out.println(apple == apple);
    System.out.println(apple == orange);
    System.out.println(apple.compareTo(apple));
    System.out.println(apple.compareTo(orange));
  }
}

3. Convert String thành Characters

public class Main {
  public static void main(String[] args) {
    String str = "DINHTHEHIEN.COM";
    int len = str.length();

    // Loop through all characters and print their indexes
    for (int i = 0; i < len; i++) {
      System.out.println(str.charAt(i) + " has index " + i);
    }
  }
}

4. Tìm kiếm trong String

public class Main {
  public static void main(String[] args) {
    String str = new String("Apple");
    int index = str.indexOf('p'); // index will have a value of 1
    System.out.println(index);

    index = str.indexOf("pl"); // index will have a value of 2
    System.out.println(index);
    index = str.lastIndexOf('p'); // index will have a value of 2
    System.out.println(index);

    index = str.lastIndexOf("pl"); // index will have a value of 2
    System.out.println(index);

    index = str.indexOf("k"); // index will have a value of -1
    System.out.println(index);
  }
}

5. Tìm vi trí xâu trong String

public class Main {
  public static void main(String[] args) {
    String str = "This is a test";
    // Test str, if it starts with "This"
    if (str.startsWith("This")) {
      System.out.println("String starts with This");
    } else {
      System.out.println("String does not start with This");
    }
    // Test str, if it ends with "program"
    if (str.endsWith("program")) {
      System.out.println("String ends with program");
    } else {
      System.out.println("String does not end with program");
    }
  }
}

6. Cắt String

public class Main {
  public static void main(String[] args) {
    String str = "A,B,C,D";
    // Split str using a comma as the delimiter
    String[] parts = str.split(",");

    // Print the the string and its parts
    System.out.println(str);

    for (String part : parts) {
      System.out.println(part);
    }
  }
}

7. Convert String

public class Main {
  public static void main(String[] args) {
    String s1 = String.valueOf('C'); // s1 has "C"
    String s2 = String.valueOf("10"); // s2 has "10"
    String s3 = String.valueOf(true); // s3 has "true"
    String s4 = String.valueOf(2014); // s4 has "2014"
  }
}

8. Replacing xâu trong String

public class Main {
  public static void main(String[] args) {
    String oldStr = new String("tooth");
    String newStr = oldStr.replace('o', 'e');
    System.out.println(newStr);
  }
}

9. Swtich String

public class Main {
  public static void main(String[] args) {
    String status = "off";
    switch (status) {
      case "on":
        System.out.println("Turn on");
        break;
      case "off":
        System.out.println("Turn off");
        break;
      default:
        System.out.println("Unknown command");
        break;
    }
  }
}

10. Switch Compare String

public class Main {
  public static void main(String[] args) {
    operate("on");
    operate("off");
    operate("ON");
    operate("Nothing");
    operate("OFF");
    operate("No");
    operate("On");
    operate("OK");
    operate(null);
    operate("Yes");
  }

  public static void operate(String status) {
    // Check for null
    if (status == null) {
      System.out.println("status cannot be null.");
      return;
    }
    status = status.toLowerCase();
    switch (status) {
    case "on":
      System.out.println("Turn on");
      break;
    case "off":
      System.out.println("Turn off");
      break;
    default:
      System.out.println("Unknown command");
      break;
    }
  }
}

5 (100%) 1 vote
Đinh Thế Hiển
 

Mình là người thích viết lách, chia sẻ các trải nghiệm trong cuộc sống. Thích thể thao đặc biệt là thể hình. Hãy kết nối với mình nhé.

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