关于“‘c‘ argument has 1 elements, which is not acceptable for use with ‘x‘ with size 300“的解决办法

以下代码

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

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 300, 'y' with size 300.

修改为：

import operator
from functools import reduce

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

即可解决