numpy之函数pad

numpy之填充函数pad

1. 使用方法
   numpy.pad(array, pad_width, mode, **kwargs)[source]

array表示待填充编内距的矩阵；
pad_width表示在每个矩阵上的填充宽度；
mode表示填充模式

2. 示例：

>>> a
array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11])

>>> a_pad=np.pad(a,(2,),mode='constant', constant_values=0)
>>> a_pad
array([ 0,  0,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,  0,  0])

>>> b=a.reshape(2,2,3)
>>> b
array([[[ 0,  1,  2],
        [ 3,  4,  5]],

       [[ 6,  7,  8],
        [ 9, 10, 11]]])
>>> b_pad=np.pad(b,((0,),(2,),(3,)),mode='constant',constant_values=0)
>>> b_pad
array([[[ 0,  0,  0,  0,  0,  0,  0,  0,  0],
        [ 0,  0,  0,  0,  0,  0,  0,  0,  0],
        [ 0,  0,  0,  0,  1,  2,  0,  0,  0],
        [ 0,  0,  0,  3,  4,  5,  0,  0,  0],
        [ 0,  0,  0,  0,  0,  0,  0,  0,  0],
        [ 0,  0,  0,  0,  0,  0,  0,  0,  0]],

       [[ 0,  0,  0,  0,  0,  0,  0,  0,  0],
        [ 0,  0,  0,  0,  0,  0,  0,  0,  0],
        [ 0,  0,  0,  6,  7,  8,  0,  0,  0],
        [ 0,  0,  0,  9, 10, 11,  0,  0,  0],
        [ 0,  0,  0,  0,  0,  0,  0,  0,  0],
        [ 0,  0,  0,  0,  0,  0,  0,  0,  0]]])