Create an easy to use object from a Redis sorted set

redisZsetWorker.js

// ## redisZsetWorker
// Requires Underscore.js
// http://documentcloud.github.com/underscore/
//
// Creates an easy to use object from a Redis sorted set.
//
// * Calculate to total, min and max of all scores
// * Calculate a font size (default: 1-10) to create a tag cloud
// * Calculate the percentage for each item
//
// Input: A Redis sorted set: zrevrange key 0 -1 WITHSCORES
// `["apples","12","oranges","8","bananas","4"]`
// 
// The reply looks like this:
//
//     {total:24, minv: 4, maxv: 12, rows: [
//         { n: "apples",
//           v: 12,
//           p: 0.5,
//           s: 10},
//           ...
//     ]}
//
// The rows array contains:
// 
// * n : the item - usually a string
// * v : the total value for this this item
// * p : the percentage
// * s : the font size
redisZsetWorker = function (v, steps) {
	var o = { total: 0, minv: 9999999, maxv: 0, rows: [] },
		steps = arguments.length > 1 ? steps : 10;
	_.each(v, function (e, i) {
		if (i%2) {
			e = Number(e);
			if (e > o.maxv) o.maxv = e;
			if (e < o.minv) o.minv = e;
			o.rows.push({ n: v[i-1], v: e });
			o.total = o.total + e;
		}
	})
	// Now that we have the total calculate p (the percentage)
	// and set s (the font size) depending on the steps
	// You might want to use `s` for class names like `tagsizeX` where `X` is `s`
	_.each(o.rows, function (e) {
		e.p = Math.round(e.v / o.total * 1000) / 1000;
		e.s = Math.ceil(Math.log(e.v) / Math.log(o.maxv) * (steps - 1) + 1);
	});
	return o;
}