I have a long UL list I need to break up in smaller lists containing about 20 items each.
I was thinking I could use something like
$(function() {
$("ul li:nth-child(20n)").after("</ul><ul>");
});
but that's not the case. Any idea how to use jQuery in a way that uses minimal CPU?
I would create document fragments with your removed lis and then reappend them to the location you want them. In this case, I reappended them to the body:
$(function(){
var $bigList = $('#bigList'), group;
while((group = $bigList.find('li:lt(20)').remove()).length){
$('<ul/>').append(group).appendTo('body');
}
});
Live Demo is at: http://jsbin.com/ejigu/33
Nothing quite that simple (that I'm aware of at least) unfortunately. Try this as an alternative:
$(function() {
$("ul").each(function() {
var list = $(this);
var size = 3;
var current_size = 0;
list.children().each(function() {
console.log(current_size + ": " + $(this).text());
if (++current_size > size) {
var new_list = $("<ul></ul>").insertAfter(list);
list = new_list;
current_size = 1;
}
list.append(this);
});
});
});
You could no doubt turn this into a function that takes the chunk size as an argument but I leave that as an exercise for the reader.
Here's a working example, just change the mod 5 to mod 20.
<html>
<script type="text/javascript" src="jquery-1.3.2.js"></script>
<script type="text/javascript">
function onLoad(){
var itemindex = 0;
var Jlistobj = null;
$('#list li').each(function()
{
if (itemindex % 5 == 0)
{
Jlistobj = $("<ul></ul>");
}
Jlistobj.append($(this));
$('#out_div').append(Jlistobj);
itemindex++;
});
}
</script>
<body onLoad="onLoad()">
<ul id="list">
<li>item1</li>
<li>item2</li>
<li>item3</li>
<li>item4</li>
<li>item5</li>
<li>item6</li>
<li>item7</li>
<li>item8</li>
<li>item9</li>
<li>item10</li>
<li>item11</li>
<li>item12</li>
<li>item13</li>
<li>item14</li>
<li>item15</li>
<li>item16</li>
<li>item17</li>
<li>item18</li>
<li>item19</li>
<li>item20</li>
</ul>
<div id="out_div"></div>
</body>
</html>
function:
$.fn.splitUp=function(splitBy,wrapper) {
$all= $(this).find('>*');
var fragment=Math.ceil($all.length/splitBy);
for(i=0; i< fragment; i++)
$all.slice(splitBy*i,splitBy*(i+1)).wrapAll(wrapper);
return $(this);
}
usage:
$('ul#slides').splitUp(4,'<li class=splitUp><ul>')
or:
$('div#slides').splitUp(3,'<div/>')
this one splits the menu in to pieces of approximately equal length function splitMenu(menu_id, pieces) {
var $menu = $(menu_id), group;
var splitItem = 0, totItemLen = 0, cumlen = 0;
$($menu).find('li').each(function(){ totItemLen = totItemLen + $(this).width(); });
$($menu).find('li').each(function(i){
cumlen = cumlen + $(this).width();
if ( totItemLen/pieces < cumlen && splitItem == 0) splitItem = i;
});
while((group = $($menu).find('li:lt(' + splitItem + ')').remove()).length){
$('<ul/>').attr('class',$($menu).attr('class')).append(group).appendTo($($menu).parent());
}
$($menu).remove();
}
splitMenu('#menu-footermenu', 2);
Just another version as a jQuery plugin:
jQuery.fn.splitList = function(num) {
var sublist;
while((sublist = this.find('li:gt('+(num-1)+')').remove()).length){
this.after($('<ul/>').append(sublist));
}
};
Here is another option - I haven't profiled any of the above, so go with whatever is fastest of course. It assumes the ul in question has the id of #list.
var listItemsPerList = 10;
var listItems = $("ul > li").length;
for (var i = 0; i < Math.round(listItems / listItemsPerList); i++) {
var startingItem = i * listItemsPerList;
var endingItem = (i + 1) * listItemsPerList;
if (endingItem > listItems) { endingItem = listItems };
$("ul > li").slice(startingItem, endingItem).wrapAll("<ul></ul>");
}
$("ul#list").replaceWith($("ul#list").children());
you can try something like this:
$("ul").each(function(k,v)){
split_list(v);
}
function split_list(list){
var li_num = $(list).find("li").length;
if(li_num > 20){
var new_list = $("<ul></ul>");
$(list).after(new_list);
new_list.append($(list).find("li:gt(20)"));
if(new_list.find("li").length > 20){
split_list(new_list);
}
}
}
LE: I think it can be further refined by finding up front how many new list will be createt, create those lists and move blocks of ~20 li's into the new created lists so they will be moved only once.
Here's a extension of the jQuery prototype ($.fn) object to provide a new method that can be chained to the jQuery() function.
I needed to functionality where I needed to add an element between the list that I split. That has been added as an optional parameter.
An example is available at http://jsfiddle.net/roeburg/5F2hW/
The usage of the function is like so:
$("ul").customSplitList(5);
The function is defined as follows:
// Function definition
(function ($) {
// Function is defined here ...
$.fn.customSplitList = function (indexToSplit, elementToAddInBetween) {
// Holds a reference to the element(list)
var that = this;
var subList, newList, listLength;
// Only continue if the element is a derivitive of a list
if ($(that) && ($(that).is("ul") || $(that).is("ol"))) {
// Additionally check if the length & the split index is valid
listLength = $(that).children().length;
if ($.isNumeric(indexToSplit) && indexToSplit > 0 && indexToSplit < listLength) {
// Based on list type, create a new empty list
newList = $($(that).clone(true)).empty();
while ((subList = this.find('li:gt(' + (indexToSplit - 1) + ')').remove()).length) {
newList.append(subList);
}
if (elementToAddInBetween && $(elementToAddInBetween)) {
that.after(newList);
newList.before(elementToAddInBetween);
} else {
that.after(newList);
}
}
}
};
})(jQuery);
Hope this helps.
Something like this:
var lis = $("ul > li");
for(var i = 0; i < lis.length; i+=20) {
lis.slice(i, i+20).wrapAll("<ul></li>");
}
$("ul > ul").unwrap();
