Redis ZSET Worker To create an easy to use object for statistics

rediszsetworker.coffee

# ## 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 = (v, steps) ->
  o = { total: 0, minv: 9999999, maxv: 0, rows: [] }
	steps = if arguments.length > 1 then steps else 12
	for e,i in v
		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`
	for e in o.rows
		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)
	o