#!/usr/bin/python

# -*- coding: utf-8 -*-

# Median

# Median is the middle value of data

# Data of odd length has a mid value

# but, data of even length has 2 mid values

# so their median is mean of these 2 values

# ranked parameter is to tell function

# weather data is ranked(sorted) or not

#

def median(ar, ranked = False):

if not ranked:

data = sorted(ar[:])

else:

# Don't need an else block still

# but to map program properly

# i've added it

data = ar[:]

# Data with odd length

if len(data) % 2 != 0:

# f(x) = (l(x) + 1) / 2 th term is the median of data

# but since computer starts counting from 0

# and not from 1, there is no need to add 1

# to length of data, otherwise results are

# not accurate

return data[len(data) / 2]

# Data with even length

# f(x) = [l(x) / 2 th term + (l(x) + 2) / 2th term] / 2

# 2.0 is to declare that median can be a float

# in case of even length data

return (data[len(data) / 2 - 1] + data[(len(data) + 1) / 2]) / 2.0

# Test

odd = [123, 456, 789, 101112, 131415, 161718, 192021, 222324, 252627]

even = [8, 7, 5, 2, 1, 3, 4, 6]

if median(odd, ranked = True) == 131415 and median(even) == 4.5:

# Print statements on separate lines look better

print("Median of odd data: " + str(131415))

print("Median of even data: " + str(4.5))

print("Yeah, it works!")

else:

# If algo didn't work

print("There's something wrong!")

# This median is for un-distributed/un-grouped data

# i.e. no frequencies

# plain numbers in an array