Use java's Character.isWhitespace() function to determine whether a character is a whitespace character

Use Java's Character.isWhitespace() function to determine whether a character is a whitespace character

In Java programming, you often encounter situations where you need to determine whether a character is a whitespace character. Whitespace characters refer to characters that are invisible and not printed on the screen, such as spaces, tabs, newlines, etc. Java provides the isWhitespace() function in the Character class to determine whether a character is a whitespace character.

The isWhitespace() function is a static method of the Character class and can be called directly through the class name. The definition of this function is as follows:

public static boolean isWhitespace(char ch)

isWhitespace() function accepts a char type parameter ch and returns a boolean type value indicating whether the parameter ch is White space characters. If the parameter ch is a blank character, it returns true; if the parameter ch is not a blank character, it returns false.

The following is a simple sample code that demonstrates how to use the isWhitespace() function to determine whether a character is a whitespace character:

public class CharacterWhitespaceExample {
    public static void main(String[] args) {
        char ch1 = ' ';
        char ch2 = '    ';
        char ch3 = '
';
        char ch4 = 'A';
        
        if (Character.isWhitespace(ch1)) {
            System.out.println("'" + ch1 + "' is a whitespace character.");
        } else {
            System.out.println("'" + ch1 + "' is not a whitespace character.");
        }
        
        if (Character.isWhitespace(ch2)) {
            System.out.println("'" + ch2 + "' is a whitespace character.");
        } else {
            System.out.println("'" + ch2 + "' is not a whitespace character.");
        }
        
        if (Character.isWhitespace(ch3)) {
            System.out.println("'" + ch3 + "' is a whitespace character.");
        } else {
            System.out.println("'" + ch3 + "' is not a whitespace character.");
        }
        
        if (Character.isWhitespace(ch4)) {
            System.out.println("'" + ch4 + "' is a whitespace character.");
        } else {
            System.out.println("'" + ch4 + "' is not a whitespace character.");
        }
    }
}

In this example, we define four character variables ch1 and ch2 , ch3, ch4. The variable ch1 represents the space character, the variable ch2 represents the tab character, the variable ch3 represents the newline character, and the variable ch4 represents the uppercase letter 'A'. Then, we use the isWhitespace() function to determine whether these four characters are whitespace characters and output the corresponding results.

Run the above code and the following results will be output:

' ' is a whitespace character.
'    ' is a whitespace character.
'
' is a whitespace character.
'A' is not a whitespace character.

As you can see, the isWhitespace() function correctly determines that space characters, tab characters, and newline characters are whitespace characters, and Capital letter 'A' is not a whitespace character.

In addition to the isWhitespace() function, the Character class also provides some other functions for character judgment, such as the isDigit() function to judge whether the character is a numeric character, and the isLetter() function to judge whether the character is a numeric character. For alphabetic characters, the isUpperCase() function is used to determine whether the character is an uppercase character, etc.

To summarize, using Java’s Character.isWhitespace() function can easily determine whether a character is a whitespace character. When processing strings, it is a common requirement to determine whether a character is a blank character, especially in scenarios such as user input validation and text processing. Therefore, mastering the isWhitespace() function in the Character class can provide convenience and efficiency for our Java programming.

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