A fun little example of Benford's Law

gistfile1.py

import numpy

def fib(a,b):
  "Generator for the fibonacci sequence starting at position a,b"
  while True:
    yield b
    a,b=b,a+b

def ld(v):
  "Determine the left-most digit in v"
  return (v%10) if (v<10) else ld(v//10)

def calc_hist(n,a=0,b=1):
  "Calculate the histogram of leading digits for n numbers in the fibonacci sequence starting at position a,b"
  hist=numpy.zeros(9, dtype="float")
  f=fib(a,b)
  for i in xrange(n):
    hist[ld(f.next())-1] += 1
  return hist/hist.sum()