parselastfm.rb

require 'net/http'
require 'json'

apikey = "YOURLASTFMAPIKEY" # your last.fm API key created from https://www.last.fm/api/account/create
apiroot = "http://ws.audioscrobbler.com/2.0/"

username = "aliekens" # your last.fm username
period = "12month" # overall | 7day | 1month | 3month | 6month | 12month
limit = "100" # how many results do you want?

url = apiroot + "?method=user.gettopartists&user=#{username}&limit=#{limit}&period=#{period}&api_key=#{apikey}&format=json"
puts url
uri = URI(url)
response = Net::HTTP.get(uri)
json = JSON.parse(response)

json["topartists"]["artist"].each do |artist|
  puts "#{artist["name"]}\t#{artist["playcount"]}"
end