(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

当然，你可以使用内置函数，但如果你想创建自己的函数，你可以这样做。这里的技巧是使用~运算符将正数转换为负数。例如~2 -> -3和在Python中使用负in For list将从末尾开始计数。如果你有mid == 2，那么它会从开始取第三个元素，从结束取第三个元素。

def median(data):
    data.sort()
    mid = len(data) // 2
    return (data[mid] + data[~mid]) / 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

下面是不使用中值函数就能找到中值的乏味方法:

def median(*arg):
    order(arg)
    numArg = len(arg)
    half = int(numArg/2)
    if numArg/2 ==half:
        print((arg[half-1]+arg[half])/2)
    else:
        print(int(arg[half]))

def order(tup):
    ordered = [tup[i] for i in range(len(tup))]
    test(ordered)
    while(test(ordered)):
        test(ordered)
    print(ordered)


def test(ordered):
    whileloop = 0 
    for i in range(len(ordered)-1):
        print(i)
        if (ordered[i]>ordered[i+1]):
            print(str(ordered[i]) + ' is greater than ' + str(ordered[i+1]))
            original = ordered[i+1]
            ordered[i+1]=ordered[i]
            ordered[i]=original
            whileloop = 1 #run the loop again if you had to switch values
    return whileloop

这很简单;

def median(alist):
    #to find median you will have to sort the list first
    sList = sorted(alist)
    first = 0
    last = len(sList)-1
    midpoint = (first + last)//2
    return midpoint

你可以这样使用返回值median = median(anyList)

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])