regulaaravaldised

Regulaaravaldised, known in English as regular expressions or regex, are sequences of characters that define a search pattern. They are a powerful tool for pattern matching within strings and are widely used in programming, text editing, and data validation.

A regular expression consists of ordinary characters, which match themselves, and metacharacters, which have special meanings. Common metacharacters include dots (.), which match any single character; asterisks (*), which match zero or more occurrences of the preceding character or group; and plus signs (+), which match one or more occurrences. Square brackets ([]) define a character set, matching any single character within the brackets. Parentheses (()) are used for grouping expressions.

The primary use of regular expressions is to search for specific patterns in text. For example, a regex can be used to find all email addresses in a document, validate phone numbers, or extract specific data from log files. They can also be used for replacing text that matches a pattern with other text.

Different programming languages and tools have their own implementations of regular expression engines, which may have slight variations in syntax or supported features. Despite these differences, the core concepts of regular expressions remain consistent across most platforms. Their flexibility and efficiency make them an indispensable tool for anyone working with text data.