python代码错误.ValueError:y应该是一个1d数组，而得到一个形状为(56000，10)的数组

Question

import numpy as np 
import pandas as pd 
import matplotlib.pyplot as plt
import seaborn as sns
from sklearn.linear_model import LogisticRegression
logistic_regression = LogisticRegression(random_state = 10)
logistic_regression.fit(X_train, y_train)
y_pred_logistic_regression = logistic_regression.predict(X_test)
print(y_pred_logistic_regression.shape)

ValueError：y应该是1d数组，得到的是形状为(56000，10(的数组，而不是

Answer 1

您的y_train数组变形了，假设您使用的是一个热编码类，解决方案是将其转换为类索引数组：

logistic_regression.fit(X_train, y_train.argmax(axis=1))

示例：

>> y_train
array([[0., 0., 1., 0., 0., 0., 0., 0., 0., 0.],
[0., 0., 0., 1., 0., 0., 0., 0., 0., 0.],
[0., 0., 0., 0., 1., 0., 0., 0., 0., 0.],
[1., 0., 0., 0., 0., 0., 0., 0., 0., 0.]])
# after conversion:
>> y_train.argmax(axis=1)
array([2, 3, 4, 0])