Use java's StringBuilder.substring() function to intercept the substring of a string

Use java's StringBuilder.substring() function to intercept the substring of a string

In Java programming, it is often necessary to operate on strings. One of the common operations is to intercept the substring of a string. . Java provides a variety of methods to achieve this function, among which the substring() function of the StringBuilder class is a simple and efficient method.

StringBuilder is a class used to operate strings in Java. It provides many methods to modify and process strings. The substring() function is one of them, which can be used to intercept some characters in the StringBuilder object.

The following is an example of using the substring() function to intercept a string substring:

public class SubstringExample {
  public static void main(String[] args) {
    StringBuilder str = new StringBuilder("Hello, World!");

    // 使用substring()函数截取字符串的子串
    StringBuilder subStr = str.substring(0, 5);

    // 输出截取的子串
    System.out.println(subStr.toString());
  }
}

In the above example, we created a StringBuilder object str and initialized it to "Hello, World !". Then, we use the substring() function to intercept the substring "Hello" in the str object and assign the result to another StringBuilder object subStr.

The substring() function accepts two parameters. The first parameter is the starting position of the substring to be intercepted (inclusive), and the second parameter is the end position of the substring to be intercepted (exclusive). . In the above example, we set the starting position to 0 and the ending position to 5, so the intercepted substring is "Hello".

Finally, we convert the StringBuilder object subStr to a String object by calling the toString() function, and output it using the System.out.println() function.

It should be noted that the substring() function returns a new StringBuilder object, not a reference to the original object. This means that any modifications to the truncated substring object will not affect the contents of the original object.

In addition to intercepting some characters, the substring() function can also be used to copy the entire string. We can set the starting position to 0 and the ending position to the length of the string to copy the entire string.

To sum up, using Java’s StringBuilder.substring() function can easily intercept the substring of a string. It is an efficient and flexible method suitable for handling various string operation scenarios. In the actual coding process, we can choose the appropriate interception method according to specific needs to improve the readability and efficiency of the code.

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