iRegEx - easy to use, easy to learn, easy to create regular expression patterns.
Features:
• real time results: shows results as you type;
• match highlightings;
• syntax validation;
• ability to replace matches;
• ability to highlight each separate regex group in a match;
• contains regex syntax library and samples: double click entries to insert them into your expression;
• will fit needs not only someone who is learning regex syntax, but also needs of people who already know it.