Replaces one or all matches of a pattern with a new string. Pattern can be string or RegExp object. Original string remains unchanged. Only first occurrence of string pattern is replaced
Regular expressions are a specialized programming language embedded in Python. REs specify rules for matching strings and performing various operations. Patterns are compiled into bytecodes executed by a C matching engine
Regular expressions provide Perl-like string matching capabilities. Supports Unicode and 8-bit strings, but not mixed types. Uses backslash for special characters and escaping. Patterns can be concatenated to form complex expressions
Regular expressions are used for pattern matching in Java. \\s represents any whitespace character including spaces, tabs, and line breaks. Double backslash (\\s) is used in Java due to syntax limitations
Wildcards are symbols used to represent one or more characters. Asterisk (*) matches any character zero or more times. Question mark (?) matches a single character once. Percent (%) matches any character zero or more times in SQL
PostgreSQL offers three pattern matching approaches: LIKE, SIMILAR TO, and POSIX regular expressions. LIKE operator returns true if string matches pattern, using underscore (_) and percent (%). SIMILAR TO operator uses regular expressions with additional metacharacters. POSIX regular expressions provide more powerful pattern matching capabilities