What is a Regular Expression (Regex)?
Regular Expression (also known as Regex, Regexp) is a special sequence of characters that defines a search pattern. The Regex language is often considered a nightmare to read by IT students due to its bizarre syntax, but it is extremely popular across all backend and frontend languages (Java, PHP, JS, Python...).
When to use Regex Online Tester?
It would be torture if you write Regex yourself and Test Debug using Terminal because you can't see the whole picture. Regex Tester helps you:
- Validate Form: Prepare absolutely correct Regex for "Email" or "Phone number" before pasting the code into HTML/JS. The highlight effect helps you see what it missed.
- Log Scraping: Extract the exact Data Format you want from a cluttered website. Extract product prices (USD), extract list of Links (\href="(...)").
- Common Format Flags:
g= global match the entire string;i= ignore case insensitive;m= multi-line when containing line breaks.