为什么没有打印线和估计系数NaN？

Question

代码使用numpy.genfromtxt将数据集导入代码，然后尝试通过散点图绘制回归线。但是，散点图打印而行不打印。此外，估计系数输出NaN。问题出在哪里？

import numpy as np 
import matplotlib.pyplot as plt 
from numpy import genfromtxt

def estimate_coef(x, y): 
    # number of observations/points 
    n = np.size(x) 

    # mean of x and y vector 
    m_x, m_y = np.mean(x), np.mean(y) 

    # calculating cross-deviation and deviation about x 
    SS_xy = np.sum(y*x) - n*m_y*m_x 
    SS_xx = np.sum(x*x) - n*m_x*m_x 

    # calculating regression coefficients 
    b_1 = SS_xy / SS_xx 
    b_0 = m_y - b_1*m_x 

    return(b_0, b_1) 

def plot_regression_line(x, y, b): 
    # plotting the actual points as scatter plot 
    plt.scatter(x, y, color = "m", 
               marker = "o", s = 30) 

    # predicted response vector 
    y_pred = b[0] + b[1]*x 

    # plotting the regression line 
    plt.plot(x, y_pred, color = "g") 

    # putting labels 
    plt.xlabel('x') 
    plt.ylabel('y') 

    # function to show plot 
    plt.show() 

def main(): 
    # observations 
    x = genfromtxt('/Users/divyanshuvarma/Downloads/graduate-admissions/Admission_Predict.csv', delimiter=',',usecols=(1))
    y = genfromtxt('/Users/divyanshuvarma/Downloads/graduate-admissions/Admission_Predict.csv', delimiter=',',usecols=(8))


    # estimating coefficients 
    b = estimate_coef(x, y) 
    print("Estimated coefficients:\nb_0 = {}  \
          \nb_1 = {}".format(b[0], b[1])) 

    # plotting regression line 
    plot_regression_line(x, y, b) 

if __name__ == "__main__": 
    main() 

Answer 1

功能b_1 = SS_xy / SS_xx有一个部门estimate_coef。你打印出值SS_xx，也许它是零？希望有所帮助。

Answer 2

问题在于csv文件。 Numpy.genfromtxt还读取了csv文件的第一行，该文件具有后续行中所遵循的值的名称（标签）。所以我使用skip_header = 1来阻止它读取字符串值。