gistfile1.py

def lexical_diversity(text):
    return len(text) / (len(set(text)) + 0.0)     #the addition of 0.0 ensures floating point division, incase you haven't executed: from __future__ import division

def hapax_count(freqdist):
    return len(freqdist.hapaxes())

def vocabulary_size(freqdist):
    return len(freqdist)

print "Lexical diversity: %s" % lexical_diversity(my_text)
print "Number of hapaxes: %s" % hapax_count(my_freqdist)
print "Vocabulary size  : %s" % vocabulary_size(my_freqdist)