Python statistics harmonic_mean()用法及代碼示例

諧波均值(也稱為“相反均值”)是幾種平均值之一，尤其是勾股均值之一。通常用於需要平均費率的情況。調和平均值也是給定一組觀測值的倒數的算術平均值的倒數。

例如，harmonic mean 1、4和4的計算公式如下：

可以使用來自的harmonic_mean()函數將諧波均值合並到Python3中statistics模塊。

用法： harmonic_mean([data-set])

參數：
[data-set]：是實數值的列表，元組或迭代器。

Returntype:返回給定數據集的harmonic_mean。

錯誤和異常：

StatisticsError當傳遞空的data-set時，或者data-set由負值組成時。
TypeError用於非數字類型值的數據集。

注意：僅使用列表，集合或任何序列中的正值來計算諧波均值。

代碼1：

# Python3 code to demonstrate the  
# working of harmonic_mean() function 
  
# Import statistics module 
import statistics 
  
# list of positive real valued numbers 
data = [1, 3, 5, 7, 9] 
  
# using harmonic mean function to calculate 
# the harmonic mean of the given data-set 
print("Harmonic Mean is % s " % (statistics.harmonic_mean(data)))

輸出：

Harmonic Mean is 2.797513321492007

代碼2：

# Python3 program to demonstrate harmonic_mean() 
# function from the statistics module 
  
# Importing the statistics module 
from statistics import harmonic_mean 
  
# Importing fractions module as fr 
from fractions import Fraction as fr 
  
# tuple of positive integer numbers 
data1 = (2, 3, 4, 5, 7, 9, 11) 
  
# tuple of a set of floating point values 
data2 = (2.4, 5.1, 6.7, 8.9) 
  
# tuple of a set of fractional numbers 
data3 = (fr(1, 2), fr(44, 12), fr(10, 3), fr(2, 3)) 
  
# dictionary of a set of values 
# Only the keys are taken in 
# consideration by harmonic_mean() 
data4 = {1:"one", 2:"two", 3:"three"} 
  
# Printing the harmonic mean of above datsets 
print("Harmonic Mean of data set 1 is % s" 
                 % (harmonic_mean(data1))) 
                   
print("Harmonic Mean of data set 2 is % s" 
                 % (harmonic_mean(data2))) 
  
print("Harmonic Mean of data set 3 is % s" 
                 % (harmonic_mean(data3))) 
                   
print("Harmonic Mean of data set 4 is % s" 
                % (harmonic_mean(data4)))

輸出：

Harmonic Mean of data set 1 is 4.299197943900386
Harmonic Mean of data set 2 is 4.574783168721765
Harmonic Mean of data set 4 is 55/56
Harmonic Mean of data set 5 is 1.6363636363636365

代碼3：示範StatisticsError

# Python code to demonstrate StatisticsError 
# while using harmonic_mean() 
  
# importing statistics module 
import statistics 
  
# data-set of numbers containing 
# a negative number 
dat1 = [1, -1] 
  
# Statistics Error is raised when the 
# data-set passed as parameter is  
# empty or contain a negative value 
print(statistics.harmonic_mean(dat1))

輸出：

Traceback (most recent call last):
  File "C:/Users/Souveek/PycharmProjects/Test.py", line 12, in 
    print(statistics.harmonic_mean((1, -1)))
  File "C:\Users\Souveek\AppData\Local\Programs\Python\Python36-32\Lib\statistics.py", line 356, in harmonic_mean
    T, total, count = _sum(1/x for x in _fail_neg(data, errmsg))
  File "C:\Users\Souveek\AppData\Local\Programs\Python\Python36-32\Lib\statistics.py", line 148, in _sum
    for n, d in map(_exact_ratio, values):
  File "C:\Users\Souveek\AppData\Local\Programs\Python\Python36-32\Lib\statistics.py", line 356, in 
    T, total, count = _sum(1/x for x in _fail_neg(data, errmsg))
  File "C:\Users\Souveek\AppData\Local\Programs\Python\Python36-32\Lib\statistics.py", line 285, in _fail_neg
    raise StatisticsError(errmsg)
statistics.StatisticsError:harmonic mean does not support negative values

注意：以下代碼可能無法在在線IDE上運行，因為harmonic_mean()函數是Python3.6中新引入的

應用範圍：
諧波均值是金融中許多重要工具(根據統計)。加權諧波平均值是平均乘數的優選方法，例如price-earnings比(P /E)，其中價格在分子內。它也用於算術平均值over-estimates為所需結果的地方的計算中。

相關用法

注：本文由純淨天空篩選整理自retr0大神的英文原創作品 Python statistics | harmonic_mean()。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。