(适用于python-2.x):

def median(lst):
    n = len(lst)
    s = sorted(lst)
    return (s[n//2-1]/2.0+s[n//2]/2.0, s[n//2])[n % 2] if n else None

>>> median([-5, -5, -3, -4, 0, -1])
-3.5

numpy.median ():

>>> from numpy import median
>>> median([1, -4, -1, -1, 1, -3])
-1.0

python 3。X，使用statistics.median:

>>> from statistics import median
>>> median([5, 2, 3, 8, 9, -2])
4.0

def median(array):
    if len(array) < 1:
        return(None)
    if len(array) % 2 == 0:
        median = (array[len(array)//2-1: len(array)//2+1])
        return sum(median) / len(median)
    else:
        return(array[len(array)//2])

一个返回给定列表中值的简单函数:

def median(lst):
    lst = sorted(lst)  # Sort the list first
    if len(lst) % 2 == 0:  # Checking if the length is even
        # Applying formula which is sum of middle two divided by 2
        return (lst[len(lst) // 2] + lst[(len(lst) - 1) // 2]) / 2
    else:
        # If length is odd then get middle value
        return lst[len(lst) // 2]

一些关于中值函数的例子:

>>> median([9, 12, 20, 21, 34, 80])  # Even
20.5
>>> median([9, 12, 80, 21, 34])  # Odd
21

如果你想使用库，你可以简单地做:

>>> import statistics
>>> statistics.median([9, 12, 20, 21, 34, 80])  # Even
20.5
>>> statistics.median([9, 12, 80, 21, 34])  # Odd
21

我为一组数字定义了一个中值函数

def median(numbers):
    return (sorted(numbers)[int(round((len(numbers) - 1) / 2.0))] + sorted(numbers)[int(round((len(numbers) - 1) // 2.0))]) / 2.0

def median(array):
    """Calculate median of the given list.
    """
    # TODO: use statistics.median in Python 3
    array = sorted(array)
    half, odd = divmod(len(array), 2)
    if odd:
        return array[half]
    return (array[half - 1] + array[half]) / 2.0

sorted()函数对此非常有用。使用排序函数 要对列表排序，只需返回中间值(或两个中间值的平均值) 如果列表包含偶数个元素，则为。

def median(lst):
    sortedLst = sorted(lst)
    lstLen = len(lst)
    index = (lstLen - 1) // 2
   
    if (lstLen % 2):
        return sortedLst[index]
    else:
        return (sortedLst[index] + sortedLst[index + 1])/2.0