# FAQ overflow

#### QUESTION

I think I must just be really tired, because this should be really simple, but it's just not working for me. I want to match a portion of a string using a regex and then access that parenthesized substring.

var myString = "something format_abc"; // I want "abc"

var arr = /(?:^|\s)format_(.*?)(?:\s|$)/(myString); console.log(arr); // prints: [" format_abc", "abc"] .. so far so good. console.log(arr[1]); // prints: undefined (???) console.log(arr[0]); // prints: format_undefined (!!!)   can anyone see what I'm doing wrong? Update: I've discovered that there was nothing wrong with the regex code above: the actual string which I was testing against was this: "date format_%A"   Reporting that "%A" is undefined seems a very strange behaviour, but not directly related to this question, so I've opened a new one here. Thanks to everyone who responded. Update: The issue was that console.log takes its parameters like a printf statement, and since the string I was logging ("%A") had a special value, it was trying to find the value of the next parameter. Since this was just a silly bug on my part, I'll now close this question. #### ANSWER You can access capturing groups like this: var myString = "something format_abc"; var myRegexp = /(?:^|\s)format_(.*?)(?:\s|$)/g;
var match = myRegexp.exec(myString);


match = myregexp.exec(myString);