jQuery .each() method

Question

I'm using jQuery to implement pagination.
Online I found a very short, simple way to do this. I've tested it and it works (displays no more than 10 items per page), but I do not fully understand it yet:
```javascript
var pageSize = 10;
var showPage = function(page) {
    $(".content").hide();
    $(".content").each(function(n) {
        if (n >= pageSize * (page - 1) && n < pageSize * page)
            $(this).show();
    });        
}
showPage(1);
$("#pagin li a").click(function() {
    $("#pagin li a").removeClass("current");
    $(this).addClass("current");
    showPage(parseInt($(this).text())) 
});
```
The part that is confusing me is the event handler inside of .each(). I'm curious as to what the n represents. Does this represent the index? Does n simply work as a counter? And the reason it works as a counter is due to the jQuery library making it work this way?
That's my best guess for now. Hoping someone can confirm or elaborate.

Steven Parker · Answer

:point_right: The n represents the item index.
This is explained in the JQuery API page for .each (http://api.jquery.com/each/).  The function is called for every element that was selected and the argument indicates the item's index in the collection.  And this represents the element itself.

Kyle Vassella · Answer

Thanks Steven. I think I didn't realize on that api page that 'index' is simply a placeholder and really anything can be written there to represent it.
My only other question would be the following math:
if (n >= pageSize * (page - 1) && n < pageSize * page)
When I break it down and plug an index value into n it makes sense and works. My concern is that if I were on my own, I don't think I'd be able to think up this math on my own. Sure, in this case and others I technically didn't need to since I can just look it up. But how does one get to the point where you can just think problems out in this way? I'm sure writing the problem out as a plan, as Andrew Chalkley teaches, would help. But I don't think I'm there yet. Does this just come with time? Should I try my best right now to be able to think up and write math operations like this on the fly, or is my time more efficiently spent 'looking it up online' at this point?
AKA how important is that ability? (to think up and write math operators like that on the fly)

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Kyle Vassella

Kyle Vassella

jQuery .each() method

2 Answers

Steven Parker

Steven Parker

The n represents the item index.

Kyle Vassella

Kyle Vassella