【问题标题】:Is there a way to suitably adjust this sklearn logistic regression function to account for multiple independent variables and fixed effects?有没有办法适当调整这个 sklearn 逻辑回归函数来解释多个自变量和固定效应?
【发布时间】:2021-11-03 23:00:20
【问题描述】:

我想调整下面包含的 LogitRegression 函数以包含其他自变量和固定效应。

以下代码改编自此处提供的答案:how to use sklearn when target variable is a proportion

from sklearn.linear_model import LinearRegression
from random import choices
from string import ascii_lowercase
import numpy as np
import pandas as pd

class LogitRegression(LinearRegression):

    def fit(self, x, p):
        p = np.asarray(p)
        y = np.log(p / (1 - p))
        return super().fit(x, y)

    def predict(self, x):
        y = super().predict(x)
        return 1 / (np.exp(-y) + 1)
    

if __name__ == '__main__':
    
    ### 1. Original version with a single independent variable
    # generate example data

    np.random.seed(42)
    n = 100
    
    ## orig version provided in the link - single random independent variable
    x = np.random.randn(n).reshape(-1,1)
    
    # defining the predictor (dependent) variable (a proportional value between 0 and 1)
    noise = 0.1 * np.random.randn(n).reshape(-1, 1)
    p = np.tanh(x + noise) / 2 + 0.5
    
    # applying the model - this works
    model = LogitRegression()
    model.fit(x, p) 

    ### 2. Adding additional independent variables and a fixed effects variable
    # creating 3 random independent variables
    x1 = np.random.randn(n)
    x2 = np.random.randn(n)
    x3 = np.random.randn(n)
    
    # a fixed effects variable
    cats = ["".join(choices(["France","Norway","Ireland"])) for _ in range(100)]

    # combining these into a dataframe
    df = pd.DataFrame({"x1":x1,"x2":x2,"x3":x3,"countries":cats})

    # adding the fixed effects country columns
    df = pd.concat([df,pd.get_dummies(df.countries)],axis=1)
                 
    print(df)

    # ideally I would like to use the independent variables x1,x2,x3 and the fixed
    # effects column, countries, from the above df but I'm not sure how best to edit the
    # LogitRegression class to account for this. The dependent variable is a proportion.
    # x = np.array(df)
    
    model = LogitRegression()
    model.fit(x, p) 

我希望预测输出的比例介于 0 和 1 之间。我之前尝试过 sklearn 线性回归方法,但这给出了超出预期范围的预测。我也研究过使用 statsmodels OLS 函数,但虽然我可以包含多个自变量,但我找不到包含固定效应的方法。

提前感谢您对此提供的任何帮助,或者如果我可以使用其他合适的方法,请告诉我。

【问题讨论】:

    标签: python machine-learning scikit-learn statistics logistic-regression


    【解决方案1】:

    在使用数据框将独立和固定效果变量传递给函数时,我设法通过以下小调整解决了这个问题(写出问题的简化示例对我找到答案有很大帮助):

    from sklearn.linear_model import LinearRegression
    from random import choices
    from string import ascii_lowercase
    import numpy as np
    import pandas as pd
    
    class LogitRegression(LinearRegression):
    
        def fit(self, x, p):
            p = np.asarray(p)
            y = np.log(p / (1 - p))
            return super().fit(x, y)
    
        def predict(self, x):
            y = super().predict(x)
            return 1 / (np.exp(-y) + 1)
        
    
    if __name__ == '__main__':
        
        # generate example data
        np.random.seed(42)
        n = 100
        
        x = np.random.randn(n).reshape(-1,1)
        
        # defining the predictor (dependent) variable (a proportional value between 0 and 1)
        noise = 0.1 * np.random.randn(n).reshape(-1, 1)
        p = np.tanh(x + noise) / 2 + 0.5
        
        # creating 3 random independent variables
        x1 = np.random.randn(n)
        x2 = np.random.randn(n)
        x3 = np.random.randn(n)
        
        # a fixed effects variable
        cats = ["".join(choices(["France","Norway","Ireland"])) for _ in range(100)]
    
        # combining these into a dataframe
        df = pd.DataFrame({"x1":x1,"x2":x2,"x3":x3,"countries":cats})
    
        # adding the fixed effects country columns
        df = pd.concat([df,pd.get_dummies(df.countries)],axis=1)
                     
        print(df)
    
        # Using the independent variables x1,x2,x3 and the fixed effects column, countries, from the above df. The dependent variable is a proportion.
        # x = np.array(df)
        categories = df['countries'].unique()
        x = df.loc[:,np.concatenate((["x1","x2","x3"],categories))]
        
        model = LogitRegression()
        model.fit(x, p) 
    
    

    【讨论】:

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