Question

我有以下1D numpy数组：

li = array([ 0.002,  0.003,  0.005,  0.009])

li.shape
(4L,)

我想制作一个形状为（4L，5L）的2D numpy数组（li_2d），如下所示：

li_2d = array([[  0.002,   0.002,   0.002,  0.002,  0.002],
               [  0.003,   0.003,   0.003,  0.003,  0.003],
               [  0.005,   0.005,   0.005,  0.005,  0.005]
               [  0.009,   0.009,   0.009,  0.009,  0.009]])

是否有一些numpy功能呢？谢谢

Answer 1

您可以使用numpy.tile获得所需的形状：

li = np.array([ 0.002,  0.003,  0.005,  0.009])
np.tile(li.reshape(4, 1), (1, 5))

array([[ 0.002,  0.002,  0.002,  0.002,  0.002],
       [ 0.003,  0.003,  0.003,  0.003,  0.003],
       [ 0.005,  0.005,  0.005,  0.005,  0.005],
       [ 0.009,  0.009,  0.009,  0.009,  0.009]])

Answer 2

您可以使用np.pad执行此操作。首先，将数组重塑为(4,1)形状，然后在边缘填充4列：

In [18]: np.pad(li.reshape(4,1),((0,0),(0,4)),mode='edge')
Out[18]: 
array([[ 0.002,  0.002,  0.002,  0.002,  0.002],
       [ 0.003,  0.003,  0.003,  0.003,  0.003],
       [ 0.005,  0.005,  0.005,  0.005,  0.005],
       [ 0.009,  0.009,  0.009,  0.009,  0.009]])

Answer 3

您也可以使用numpy.repeat：

执行此操作

In [5]: np.repeat(li, 5).reshape(li.shape[0], 5)
Out[5]: 
array([[ 0.002,  0.002,  0.002,  0.002,  0.002],
       [ 0.003,  0.003,  0.003,  0.003,  0.003],
       [ 0.005,  0.005,  0.005,  0.005,  0.005],
       [ 0.009,  0.009,  0.009,  0.009,  0.009]])

您可以使用numpy.tile或转置运算符来获得转置：

In [8]: np.tile(li, 5).reshape(5, li.shape[0])
Out[8]: 
array([[ 0.002,  0.003,  0.005,  0.009],
       [ 0.002,  0.003,  0.005,  0.009],
       [ 0.002,  0.003,  0.005,  0.009],
       [ 0.002,  0.003,  0.005,  0.009],
       [ 0.002,  0.003,  0.005,  0.009]])

In [9]: np.repeat(li, 5).reshape(li.shape[0], 5).T
Out[9]: 
array([[ 0.002,  0.003,  0.005,  0.009],
       [ 0.002,  0.003,  0.005,  0.009],
       [ 0.002,  0.003,  0.005,  0.009],
       [ 0.002,  0.003,  0.005,  0.009],
       [ 0.002,  0.003,  0.005,  0.009]])

从1D numpy数组中制作2D

3 个答案: