[DeepLearning]吴恩达Coursera课后作业

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吴恩达课后作业整合

https://blog.csdn.net/u013733326/article/details/79827273

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问题集合

课程1_第3周_编程作业

（1）

# Visualize the data:
plt.scatter(X[0, :], X[1, :], c=Y, s=40, cmap=plt.cm.Spectral);

报错：

ValueError: 'c' argument has 1 elements, which is not acceptable for use with 'x' with size 400, 'y' with size 400.

解决：

修改为

 plt.scatter(X[0, :], X[1, :], c=squeeze(Y), s=40, cmap=plt.cm.Spectral);

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（2）

# Plot the decision boundary for logistic regression
plot_decision_boundary(lambda x: clf.predict(x), X, Y)

报错：

ValueError: RGBA sequence should have length 3 or 4

During handling of the above exception, another exception occurred:

……

ValueError: 'c' argument has 1 elements, which is not acceptable for use with 'x' with size 400, 'y' with size 400.

解决：

将  plt.scatter(X[0, :], X[1, :], c=y, cmap=plt.cm.Spectral)

修改为 plt.scatter(X[0, :], X[1, :], c=squeeze(y), cmap=plt.cm.Spectral)  不起作用

将plot_decision_boundary函数中的：plot_decision_boundary(lambda x: clf.predict(x), X, Y)  

修改为  plot_decision_boundary(lambda x: clf.predict(x), X, Y.ravel())  成功解决

原因：c 需要一维的array