Question 1

What is a regular expression?

Accepted Answer

A regular expression (regex) is a pattern that describes a set of strings. It is used for searching, matching, and replacing text. Common uses include form validation, text parsing, and data extraction.

Question 2

What regex flavors are supported?

Accepted Answer

This tool generates JavaScript-compatible regular expressions. Most patterns also work in Python, Java, C#, and other languages with minor syntax differences. Flags like g (global) and i (case-insensitive) are standard across engines.

Question 3

How do I match special characters?

Accepted Answer

Special regex characters (. * + ? ^ $ { } [ ] ( ) | \) must be escaped with a backslash. For example, to match a literal dot, use \. instead of just a dot, which matches any character.

Question 4

What are common regex patterns?

Accepted Answer

Common patterns include: email (\S+@\S+\.\S+), URL (https?://\S+), phone numbers (\d{3}-\d{3}-\d{4}), dates (\d{4}-\d{2}-\d{2}), and IP addresses (\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).

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