Emebdly solution #2

gistfile1.py

from HTMLParser import HTMLParser
from operator import add
from math import sqrt, pow
import requests

class EmbedlyParser(HTMLParser):
    depth = 1
    ps = []
    article = False

    def handle_starttag(self, tag, atrs):
        if tag == 'article':
            self.article = True

        if self.article:
            if tag != 'p':
                self.depth += 1
            else:
                self.ps.append(self.depth)

    def handle_endtag(self, tag):
        if tag == 'article':
            self.article = False
        if self.article and tag != 'p':
            self.depth -= 1

if __name__ == "__main__":
    r = requests.get("http://apply.embed.ly/static/data/2.html")
    parser = EmbedlyParser()
    parser.feed(r.content)

    mean = float(reduce(add, parser.ps))/float(len(parser.ps))
    dif_sq = [pow((p - mean),2) for p in parser.ps]
    dif_sq_mean = float(reduce(add, dif_sq))/float(len(dif_sq))
    dev = sqrt(dif_sq_mean)
    print "Deviation is %f" %dev