What are the methods to clear stringbuilder?

StringBuilder is a class in Java used to operate strings. It provides a series of methods to add, delete, modify and other operations on strings. In practical applications, sometimes we need to clear the contents of a StringBuilder object in order to reuse it. This article will introduce several methods for clearing StringBuilder and how to use these methods.

1. Use the setLength(0) method to clear the StringBuilder object:

The setLength(0) method of the StringBuilder object can set its length to 0, thereby clearing the contents of the StringBuilder object. The sample code is as follows:

java
StringBuilder sb = new StringBuilder("Hello World");
sb.setLength(0);
System.out.println(sb.toString()); // 输出为空字符串

2. Use the delete(0, length) method to clear the StringBuilder object:

The delete(0, length) method of the StringBuilder object can delete from index 0 to the specified length. characters, thus clearing the contents of the StringBuilder object. The sample code is as follows:

java
StringBuilder sb = new StringBuilder("Hello World");
sb.delete(0, sb.length());
System.out.println(sb.toString()); // 输出为空字符串

3. Use the replace(0, length, "") method to clear the StringBuilder object:

The replace(0, length, "") method of the StringBuilder object can be Characters starting from index 0 to the specified length are replaced with empty strings, thereby clearing the contents of the StringBuilder object. The sample code is as follows:

java
StringBuilder sb = new StringBuilder("Hello World");
sb.replace(0, sb.length(), "");
System.out.println(sb.toString()); // 输出为空字符串

4. Use new StringBuilder() to re-create a new StringBuilder object:

Another way to clear the StringBuilder object is to replace it by creating a new StringBuilder object the original object. The sample code is as follows:

java
StringBuilder sb = new StringBuilder("Hello World");
sb = new StringBuilder();
System.out.println(sb.toString()); // 输出为空字符串

Summary:

The above are several commonly used methods to clear StringBuilder objects. Choose the appropriate method to clear based on specific needs and scenarios. In actual applications, we can choose the appropriate method based on the size and frequency of use of the StringBuilder object to improve the efficiency and performance of the code.

It should be noted that clearing the StringBuilder object does not release the memory space, but only clears its contents for reuse. If you need to free up memory space, you can set the StringBuilder object to null and let Java's garbage collection mechanism automatically reclaim the memory.

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