机器学习常用语法python

插入数据

在X的第一列插入1

X = np.insert(X, 0, values = np.ones(X.shape[0]), axis = 1)

随机选取一些数据

在X中随机选取100个样本

sample_id = np.random.choice(np.arange(X.shape[0]), 100)

优化训练

用到的时候查一下文档

import scipy.optimize as opt
res = opt.minimize(fun = cost_function, x0 = theta, args = (X, y, learning_rate), method = 'TNC', jac = cost_function_gradient, options = {'disp' : True})
final_theta = res.x

轴向最大值的索引

y_pred = np.argmax(prob_matrix, axis = 1)

加载matlab数据

from scipy.io import loadmat
data = loadmat('filename.mat')
data