Standard deviations in python

Given a files salaries.csv with this structure:

City,Job,Salary
Delhi,Doctors,500
Delhi,Lawyers,400
Delhi,Plumbers,100
London,Doctors,800
London,Lawyers,700
London,Plumbers,300
Tokyo,Doctors,900
Tokyo,Lawyers,800
Tokyo,Plumbers,400
...

... print the standard deviation of salaries by profession.

Sample output

Plumbers 311
Lawyers 286
Doctors 448

Solution

from __future__ import with_statement

from math import sqrt

def get_stats(profession, salaries):   

  n = float(len(salaries))

  mean = sum(salaries)/n

  stdev = 0

  for value in salaries:

    stdev += (value - mean)**2

  stdev = (stdev/(n))**0.5

  print profession, stdev

with open('salaries.csv') as f:

  f.readline()

  # Create the list of salaries 

  salaries = {} 

  for line in f.readlines():

    country, profession, value = line.split(',')

    value = int(value.strip())

    profession = profession.strip()

    if salaries.has_key(profession):

        salaries[profession].append(value)

    else:

        salaries[profession] = [value]

  for k,v in salaries.items():

    get_stats(k,v)