CODEWITHSUNDEEP
javascriptregex
hawaiijim
hawaiijim

Reputation: 1

How to extract the last substring using JavaScript regular expressions?

I am new to regular expressions. I am trying to use JavaScript regular expressions to extract the last substring within parentheses from a string. It's not working for me. Instead, I'm getting the first substring within a pair of parentheses. Can someone help me?

Here's an example. I am trying to extract the substring 'xyz', but instead I'm getting 'abc'.

var str1 = 'Hello World (abc)'; // May or may not contain parentheses
var str2 = '(xyz)'; // Definitely contains parentheses
var troublesomeString = str1 + ' ' + str2; // This is the string I'm working with

var result = myFunc(troublesomeString);
alert(result); // Should say 'xyz', but instead says 'abc'

...

function myFunc(troublesomeString) {
    // Here I am trying to get '(xyz)', but am instead getting '(abc) (xyz)'
    var resultArray = troublesomeString.match(/\(.+\)$/);
    troublesomeString = resultArray[0];

    // Here I am trying to get 'xyz', but am instead getting 'abc'
    resultArray = troublesomeString.match(/[a-z]+/); // Adding a $ after + doesn't help
    troublesomeString = resultArray[0]; // resultArray[1] is null

    return troublesomeString;
}

Upvotes: 0

Views: 1253

Answers (4)

WoooHaaaa
WoooHaaaa

Reputation: 20440

First try

You need to add \( and \):

resultArray = troublesomeString.match(/\([a-z]+\)$/);

And the result is ["(xyz)"], Note the $ there.

Last try

If you want to group out something, you should wrap () to them :

resultArray = troublesomeString.match(/\(([a-z]+)\)$/);

Note the ( ) pair.

the result is ["(xyz)", "xyz"]

And you know what to do next.

Upvotes: 1

m1kael
m1kael

Reputation: 2851

You need to use the "g" switch to perform a global search.

Here's a working example:

<script type="text/javascript">
    var str = "test (abc) (xyz)";
    var result = str.match(/\([^)]+\)/g);

    alert(result[result.length - 1]);
</script>

Upvotes: 0

Fallexe
Fallexe

Reputation: 596

Try using this regex instead of the first regex you are using: /\([^\(]+\)$/. The ^\( tells it to accept any character except a (.

As a note, you can use this site http://regexpal.com/ to help you build and test regular expressions.

Upvotes: 0

Shadow Man
Shadow Man

Reputation: 3402

You are matching everything in between the first "(" and the last ")" which must end the string.

Try this instead to match the contents of the last set of parentheses (which still must end the string as per the '$'):

var resultArray = troublesomeString.match(/\([^)]+\)$/);

Upvotes: 3

Related Questions