Regular expressions (regex) are a powerful tool used in programming for pattern matching in strings. They are widely used in various applications, such as data validation, searching, and parsing.
Basic Syntax
Here's a basic syntax of a regex pattern:
pattern = ^[a-zA-Z0-9]+$
This pattern matches a string that starts and ends with one or more alphanumeric characters.
Common Characters
.: Matches any character except a newline.*: Matches zero or more occurrences of the preceding element.+: Matches one or more occurrences of the preceding element.?: Matches zero or one occurrence of the preceding element.[]: Defines a character set. Matches any one character within the brackets.{n}: Matches exactly n occurrences of the preceding element.{n,}: Matches n or more occurrences of the preceding element.
Example
Suppose you want to match a string that starts with "en" followed by any number of alphanumeric characters. The regex pattern would be:
^en[a-zA-Z0-9]+$
Resources
For more information on regex, you can visit our Regex Tutorial.