在 Python 中查找列表的中位数 [英] Finding median of list in Python

问题描述

你如何在 Python 中找到列表的中位数?该列表可以是任意大小，并且不保证数字按任何特定顺序排列.

如果列表包含偶数个元素，则函数应返回中间两个元素的平均值.

以下是一些示例(按显示目的排序):

中值([1]) == 1中位数([1, 1]) == 1中位数([1, 1, 2, 4]) == 1.5中位数([0, 2, 5, 6, 8, 9, 9]) == 6中位数([0, 0, 0, 0, 4, 4, 6, 8]) == 2

解决方案

Python 3.4 有 statistics.median:

<块引用>

返回数值数据的中位数(中间值).

当数据点数为奇数时，返回中间的数据点.当数据点数为偶数时，取两个中间值的平均值来插值中位数:

<预><代码>>>>中位数([1, 3, 5])3>>>中位数([1, 3, 5, 7])4.0

用法:

导入统计项目 = [6, 1, 8, 2, 3]统计.中位数(项目)#>>>3

对于类型也非常小心:

statistics.median(map(float, items))#>>>3.0从十进制导入十进制statistics.median(map(Decimal, items))#>>>十进制('3')

How do you find the median of a list in Python? The list can be of any size and the numbers are not guaranteed to be in any particular order.

If the list contains an even number of elements, the function should return the average of the middle two.

Here are some examples (sorted for display purposes):

median([1]) == 1
median([1, 1]) == 1
median([1, 1, 2, 4]) == 1.5
median([0, 2, 5, 6, 8, 9, 9]) == 6
median([0, 0, 0, 0, 4, 4, 6, 8]) == 2

解决方案

Python 3.4 has statistics.median:

Return the median (middle value) of numeric data.

When the number of data points is odd, return the middle data point. When the number of data points is even, the median is interpolated by taking the average of the two middle values:

>>> median([1, 3, 5])
3
>>> median([1, 3, 5, 7])
4.0

Usage:

import statistics

items = [6, 1, 8, 2, 3]

statistics.median(items)
#>>> 3

It's pretty careful with types, too:

statistics.median(map(float, items))
#>>> 3.0

from decimal import Decimal
statistics.median(map(Decimal, items))
#>>> Decimal('3')

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