we've been having troubles with using regular expression that uses special characters such as &$%*[] 

as we're not sure which characters need to be treated differently. when we were testing it, we were using a tool called regex101.com which allows us to test out regular expressions. 

when our script was failing to find the correlation using the regular expression we created, we decided to use this tool and put the response body of where we were expecting to capture the correlation as the sample text and then using the regular expression we were using, it was able to find the correlations with out any problem. 

so we're feeling like load runner is using a different library or different definitions than what normal regular expressions are using. we know this to be true because we noticed that LR doesnt allow us to use {}  to create ranges as this is used to depict variables in load runner. so what other differences are there that we should know about?