A regex visualizer allows to visualize your regex, it helps to understand it. This feature is useful for large regexes.
Cyrilex also allows you to generate a string example from a RegEx. This gives a pretty quick idea of a regex.
Step 6: Copy and paste or directly type your substitute string in the "Substitution" field.
Step 7: Substitutions are automatically performed on your test string.
Generate a string from RegEx (Beta):
Clicks on "Generate a string from RegEx (Beta)" in order to generate a string that matches with the regex.
Substitutions are not managed.
News: You can now test MySQL regex, select the "MySQL 8" engine.
A regular expression is a sequence of characters that define a search pattern. This pattern is used by string searching algorithms for find or replace text. It can be useful to validate an EMAIL address or an IP address.
Regex support is part of the standard library of many programming languages. Each programming language has its own regex engine, regular expression implementations vary slightly between languages.
Regex humor (Jamie Zawinski):
Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems.
Cyrilex is an online regex checker, it allows to easily test and debug regex. This avoids wasting time writing the few lines of code needed to do the tests.
A regex visualizer and a regex generator help you to understand and debug your regexes.
This tool also allows you to share your regular expressions, this can be useful when you want to explain one of your regex problems (or its resolution) on a forum.
Some regex that can be useful (without warranty).
The last RFC is complex, there is no reliable solution, this regex should work more than 99% of the time (You must turn off case sensitivity).
The regex below allows to validate alphanumeric string. Be careful, \w authorizes the underscore character.
The regex below allows to validate MD5 string.
The regex below allows to validate IP v4.