python初始化数组⼤⼩_python-增加数组⼤⼩并将新元素初始
化为z
在Python中,如果输⼊是numpy数组,则可以使⽤^{}在其周围填充零-import numpy as np
A = np.array([[1, 2 ],[2, 3]]) # Input
A_new = np.lib.pad(A, ((0,1),(0,2)), 'constant', constant_values=(0)) # Output
样本运⾏-In [7]: A # Input: A numpy array
Out[7]:
array([[1, 2],
[2, 3]])
In [8]: np.lib.pad(A, ((0,1),(0,2)), 'constant', constant_values=(0))
Out[8]:
array([[1, 2, 0, 0],
[2, 3, 0, 0],
[0, 0, 0, 0]]) # Zero padded numpy array
如果您不想对要填充的0进⾏数学运算,可以让代码为您指定输出数组⼤⼩-In [29]: A
Out[29]:
array([[1, 2],
[2, 3]])
In [30]: new_shape = (3,4)
In [31]: shape_diff = np.array(new_shape) - np.array(A.shape)定义数组初始化
In [32]: np.lib.pad(A, ((0,shape_diff[0]),(0,shape_diff[1])),
'constant', constant_values=(0))
Out[32]:
array([[1, 2, 0, 0],
[2, 3, 0, 0],
[0, 0, 0, 0]])
或者,可以从初始化为零的输出数组开始,然后将这些输⼊元素从A-In [38]: A
Out[38]:
array([[1, 2],
[2, 3]])
In [39]: A_new = np.zeros(new_shape,dtype = A.dtype)
In [40]: A_new[0:A.shape[0],0:A.shape[1]] = A
In [41]: A_new
Out[41]:
array([[1, 2, 0, 0],
[2, 3, 0, 0],
[0, 0, 0, 0]])
在MATLAB中,可以使⽤^{}-A_new = padarray(A,[1 2],'post')样本运⾏->> A
A =
1 2
2 3
>> A_new = padarray(A,[1 2],'post')
A_new =
1 2 0 0
2 3 0 0
0 0 0 0

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