A character in the input string can be any character that is not a white-space character.
For more information, see White-Space Character.Ī non-white-space character. A character in the input string can be any Unicode separator character, as well as any one of a number of control characters.
For more information, see Non-Word Character.Ī white-space character. A character in the input string can belong to any Unicode category that is not a word character. For more information, see Word Character.Ī non-word character. A character in the input string can belong to any of the Unicode categories that are appropriate for characters in words. For more information, see Negative Unicode Category or Unicode Block.Ī word character. A character in the input string must not be a member of a particular Unicode category or must not fall within a contiguous range of Unicode characters for a match to succeed. For more information, see Unicode Category or Unicode Block.Ī negative general Unicode category or named block. A character in the input string must be a member of a particular Unicode category or must fall within a contiguous range of Unicode characters for a match to succeed. For more information, see Any Character.Ī general Unicode category or named block. (dot or period) character in a regular expression is a wildcard character that matches any character except \n. For more information, see Negative Character Group.Īny character. A character in the input string must not match one of a specified set of characters. For more information, see Positive Character Group. A character in the input string must match one of a specified set of characters. NET supports the following character classes: The split method is a convenience method that splits the given input sequence around matches of this pattern.A character class defines a set of characters, any one of which can occur in an input string for a match to succeed. The pattern method returns the regular expression from which this pattern was compiled. The compile method compiles the given regular expression into a pattern, then the matcher method creates a matcher that will match the given input against this pattern. Many matchers can share the same pattern because it is stateless. The resulting pattern is used to create a Matcher object that matches arbitrary character sequences against the regular expression. The following classes match character sequences against patterns specified by regular expressions.Īn instance of the Pattern class represents a regular expression that is specified in string form in a syntax similar to that used by Perl.Ī regular expression, specified as a string, must first be compiled into an instance of the Pattern class. To develop regular expressions, ordinary and special characters are used:Īny character (may or may not match line terminators)Ĭheck the documentation about the Pattern class for more specific details and examples. The simplest form of a regular expression is a literal string, such as "Java" or "programming." Regular expression matching also allows you to test whether a string fits into a specific syntactic form, such as an email address. You can use the package to find, display, or modify some or all of the occurrences of a pattern in an input sequence. Regular Expressions ConstructsĪ regular expression is a pattern of characters that describes a set of strings.
#JAVA REGEX PREDEFINED CHARACTER CLASSES INSTALL#
To compile the code in these examples and to use regular expressions in your applications, you'll need to install J2SE version 1.4. Removal of control characters from a file.
#JAVA REGEX PREDEFINED CHARACTER CLASSES HOW TO#
This article provides an overview of the use of regular expressions, and details how to use regular expressions with the package, using the following common scenarios as examples: Now functionality includes the use of meta characters, which gives regular expressions versatility. The Java 2 Platform, Standard Edition (J2SE), version 1.4, contains a new package called, enabling the use of regular expressions. This often lead to complex or messy code. To pattern match using the Java programming language required the use of the StringTokenizer class with many charAt substring methods to read through the characters or tokens to process the text. Languages like Perl, sed, or awk improves pattern matching with the use of regular expressions, strings of characters that define patterns used to search for matching text. Applications frequently require text processing for features like word searches, email validation, or XML document integrity.
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