Unicode Equivalents for w and b in Java Regular Expressions
Java's regex implementation doesn't use the w character class shorthands for "any letter, digit, or connecting punctuation" like other implementations do. This makes matching Unicode words more difficult. The issue extends to the b word separator, which also exhibits inconsistent behavior in Java.
Unicode-Aware Equivalents
To resolve these issues, one can rewrite a regex pattern using the following replacements:
Other Unicode Properties
In addition to w and b, Java's regexes lack Unicode-aware support for other properties. However, these properties can be extended by using the p syntax, as shown below:
| Java Syntax | Unicode Property |
|---|---|
| p{Lower} | Unicode Lowercase |
| p{Upper} | Unicode Uppercase |
| p{ASCII} | ASCII |
| p{Alpha} | Unicode Alphabetic |
| p{Digit} | Unicode Digit |
| p{Alnum} | Unicode Alphanumeric |
| p{Punct} | Unicode Punctuation |
| p{Graph} | Unicode Graph |
| p{Print} | Unicode Printable |
| p{Blank} | Unicode Blank |
| p{Cntrl} | Unicode Control |
| p{XDigit} | Unicode Hexadecimal Digit |
| p{Space} | Unicode Space |
Unicode-Aware Regex
By incorporating these Unicode-aware substitutes, one can create regex patterns that handle Unicode data accurately. For example, the following pattern matches Unicode words:
Pattern pattern = Pattern.compile("\w+"); // Unicode-aware \w equivalentThis pattern can be used to match words in text strings, regardless of whether the characters are ASCII or Unicode-encoded.
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