编写一个函数，对 DataFrame 列表执行多个学生 t 检验

Question

我有这个数据框：

print(TempvsDType)
              CurrentThermostatTemp
DwellingType                       
Bungalow                        0.0
Bungalow                       22.0
Bungalow                       22.0
Bungalow                       25.0
Bungalow                       18.0
Bungalow                       21.0
Bungalow                       22.0
Bungalow                       10.0
Bungalow                       18.0
Bungalow                       20.0
Bungalow                       20.0
Bungalow                       22.0
Bungalow                       20.0
Bungalow                       10.0
Bungalow                       30.0
Bungalow                       22.0
Bungalow                       20.0
Bungalow                       20.0
Bungalow                       19.0
Bungalow                       20.0
Bungalow                       22.0
Bungalow                       20.0
Bungalow                       21.0
Bungalow                       22.0
Bungalow                       15.0
Bungalow                       22.0
Bungalow                        0.0
Bungalow                       24.0
Bungalow                       30.0
Bungalow                       20.0
...                             ...
Park Home                      20.0
Park Home                      23.0
Park Home                      20.0
Park Home                      20.0
Park Home                      20.0
Park Home                      18.0
Park Home                      20.0
Park Home                      15.0
Park Home                      12.0
Park Home                      20.0
Park Home                      20.0
Park Home                      23.0
Park Home                      21.0
Park Home                      20.0
Park Home                      20.0
Park Home                      20.0
Park Home                      23.0
Park Home                      18.0
Park Home                      20.0
Park Home                      18.0
Park Home                      16.0
Park Home                      17.0
Park Home                      20.0
Park Home                      20.0
Park Home                      18.0
Park Home                      18.0
Park Home                      20.0
Park Home                      20.0
Park Home                      15.0
Park Home                      21.0

[6247 rows x 1 columns]

我已经用 .truncate() 方法分隔了每个变量：


Flat = TempvsDType.truncate(before="Flat",after="Flat")
House = TempvsDType.truncate(before="House",after="House")
Bungalow = TempvsDType.truncate(before="Bungalow",after="Bungalow")
Maisonette = TempvsDType.truncate(before="Maisonette",after="Maisonette")
ParkHome = TempvsDType.truncate(before="Park Home",after="Park Home")

我的目标是对变量之间所有可能的组合执行学生 t 检验，重复或重复对除外。但是，我不得不手动执行此操作，这非常耗时且耗时，尤其是对于其他变量超过 5 个且组合数量大幅增加的脚本。这是我的手动方法：

from scipy.stats import ttest_ind
#All possible combinations:
Flat_House = ttest_ind(Flat,House)
Flat_Bungalow = ttest_ind(Flat,Bungalow)
Flat_Maisonette = ttest_ind(Flat,Maisonette)
Flat_ParkHome = ttest_ind(Flat,ParkHome)
House_Bungalow = ttest_ind(House,Bungalow)
House_Maisonette = ttest_ind(House,Maisonette)
House_ParkHome = ttest_ind(House,ParkHome)
Bungalow_Maisonette = ttest_ind(Bungalow,Maisonette)
Bungalow_ParkHome = ttest_ind(Bungalow,ParkHome)
Maisonette_ParkHome = ttest_ind(Maisonette, ParkHome)
#t-test between each combination
print("t-test between {} and {} is {} and p-value:{}".format(u[0],u[1],Flat_House[0],Flat_House[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[0],u[2],Flat_Bungalow[0],Flat_Bungalow[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[0],u[3],Flat_Maisonette[0],Flat_Maisonette[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[0],u[4],Flat_ParkHome[0],Flat_ParkHome[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[1],u[2],House_Bungalow[0],House_Bungalow[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[1],u[3],House_Maisonette[0],House_Maisonette[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[1],u[4],House_ParkHome[0],House_ParkHome[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[2],u[3],Bungalow_Maisonette[0],Bungalow_Maisonette[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[2],u[4],Bungalow_ParkHome[0],Bungalow_ParkHome[1]))
print("t-test between {} and {} is {} and p-value:{}".format(u[3],u[4],Maisonette_ParkHome[0],Maisonette_ParkHome[1]))

因此，我想知道如何编写一个自动执行此操作的函数，即打印所有可能组合的学生 t 检验，除了重复项和现有对，并且 return 按照我的方式进行手动打印。我已经尝试了很多次，但没有 succeeded.I 如果有人能帮助我，我会很高兴。谢谢。

Answer 1

from itertools import combinations
from scipy.stats import ttest_ind

dfs = dict(tuple(TempvsDType.drop_duplicates(inplace=False).groupby('DwellingType'))) #  drop duplicate rows, and create a dictionary of dataframes after grouping by DwellingType

def ttest(pair):
    results= ttest_ind(dfs[pair[0]]['CurrentThermostatTemp'], dfs[pair[1]]['CurrentThermostatTemp'])
    print(f"t-test between {pair[0]} and {pair[1]} is {results[0]} and p-value: {results[1]}")

all_combinations = list(combinations(list(dfs.keys()), 2)) # find all combinations in the keys of the dict with dataframes
[ttest(i) for i in all_combinations] # pass all combinations through the function ttest

输出： t-test between Bungalow and Park Home is 0.2594309721800956 and p-value: 0.7984182890048678

编写一个函数，对 DataFrame 列表执行多个学生 t 检验

Write a function that performs multiple student t-test for a list of DataFrames

python

pandas

function

dataframe

scipy.stats