(Read part two.) Regular expressions are a language of string patterns built in to most modern programming languages, including Java 1.4 onward; they can be used for: searching, extracting, and modifying text. This article is part one in the series: “Regular Expressions.” Read part two for more information on lookaheads, lookbehinds, and configuring the matching engine.
To get a more visual look into how regular expressions work, try our visual java regex tester.
Because the only other online tool I could find for testing .
NET regular expressions was slow and covered with ads, I decided to write a simple AJAX regular expression tester.]]
This regular expression pattern is very useful to implement a strong and complex password.
Character classes are used to define the content of the pattern. For instance, in the first example we lost our wallet.
=.*[A-Z]) # must contains one uppercase characters (?
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