numpy.squeeze()
在吴恩达深度学习视频的作业里，经常遇到这样的情况。
代码语言：javascript复制ValueError: c of shape (1, 300) not acceptable as a color sequence for x with size 300, y with size 300这是因为matplotlib.pyplot接收的color sequence 参数c应该是单个值，直接传Y或者Y.train传的是shape(1, size)的矩阵。
解决方案：
代码语言：javascript复制import numpy as np
np.squeeze(Y)
np.squeeze(Y.train)np.squeeze这个函数的作用是去掉矩阵里维度为1的维度。
例：(1, 300)的矩阵经由np.squeeze处理后变成300; (200, 1, 300)的矩阵经由np.squeeze处理后变成(200, 300)。
详情请参阅官方文档：
代码语言：javascript复制numpy.squeeze
numpy.squeeze(a, axis=None)[source]
Remove single-dimensional entries from the shape of an array.
Parameters:
a : array_like
Input data.
axis : None or int or tuple of ints, optional
New in version 1.7.0.
Selects a subset of the single-dimensional entries in the shape. If an axis is selected with shape entry greater than one, an error is raised.
Returns:
squeezed : ndarray
The input array, but with all or a subset of the dimensions of length 1 removed. This is always a itself or a view into a.Examples
代码语言：javascript复制>>>
>>> x = np.array([[[0], [1], [2]]])
>>> x.shape
(1, 3, 1)
>>> np.squeeze(x).shape
(3,)
>>> np.squeeze(x, axis=(2,)).shape
(1, 3)
