JQuery split array elements

Question

I am trying to get the ids from some li elements. But I'm not sure how to split the results in the array. So message_1 becomes 1, message_2 becomes 2 and so on.

<ul id="chat_viewport">
<li id="message_1">message</li>
<li id="message_2">message this and that</li>
<li id="message_3">3</li>
<li id="message_4">4</li>
<li id="message_5">5</li>
</ul>
<a href="#" class="test">TEST</a>​
$("a.test").click(function(e) {
e.preventDefault();
var idarray = $("#chat_viewport")
 .find("li") //Find the li in #chat_viewport
 .map(function() { return this.id; }) //Project Ids
 .get(); //ToArray
var biggest = Math.max.apply( null, idarray );
alert(idarray);
});​

I have an example here http://jsfiddle.net/T5x5d/

• Alex Ball: try whit this if i've understend : return this.id.replace('message_', '')

Answer 1

Replace your .map function with this:

function() { return this.id.replace('message_', ''); }

Answer 2

If you are sure of the format of IDs, then you can use this:

.map(function() { return this.id.split('_')[1]; })

P.S. Put entire code in question. It is not long and if something happens to your jsFiddle, then other users won't understand the answer.

Answer 3

modify it to look like this :

$("a.test").click(function(e) {
e.preventDefault();
var idarray = $("#chat_viewport")
 .find("li") //Find the li in #chat_viewport
 .map(function() { return this.id.split('_')[1]; }) //Project Ids
 .get(); //ToArray
var biggest = Math.max.apply( null, idarray );
alert(idarray);
});

Answer 4

this is a to much but:

$("a.test").click(function(e) {
 e.preventDefault();
 var idarray = $("#chat_viewport")
 .find("li") //Find the li in #chat_viewport
 .map(function() {
 var match = /(\d+)/.exec(this.id);
 return match !== null ? parseInt(match[0]) : 0;
 }) //Project Ids
 .get(); //ToArray
 var biggest = Math.max.apply( null, idarray );
 alert(biggest);
});

i dont take to the account that it must have the id of message_ just a number in its id and convert it to a number(if you want to return an array with numbers) if no number was found it will return a 0.