How Does Java\'s Scanner Class Use Delimiters to Parse Text Data?

Understanding Delimiters in Java's Scanner Class

The Java Scanner class provides the ability to read and parse text data using a designated delimiter character or pattern.

Understanding Scanner.useDelimiter

The useDelimiter method in Scanner allows you to specify the character or regular expression that separates individual tokens of data within the input text.

Example

Consider the following code:

Scanner sc = new Scanner(new File(dataFile));
sc.useDelimiter(",|\r\n");

Here, we open a file and tell the Scanner to use the comma , or a newline character rn as the delimiters. This means that when reading from the file, the Scanner will split the input into individual tokens based on these delimiters.

Regular Expression Delimiters

In Java, you can use regular expressions as delimiters. Regular expressions provide a flexible way to specify patterns of characters to match in the input.

For example, to find all occurrences of the word "fish" in a string, you could use the delimiter \s*fish\s*. This matches any whitespace character (indicated by s) zero or more times, followed by the word "fish", followed by zero or more whitespace characters.

Custom Delimiter Syntax

The following table provides examples of common regular expression characters and their meanings:

Refer to the official Java documentation for more detailed information on regular expression syntax.

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