numpy基础——关于 ndarray 的一些尝试

In [1]: import numpy as np

In [3]: a_Mat = np.array([1,1],[1,1],[1,1])
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-3-99d92909603d> in <module>()
----> 1 a_Mat = np.array([1,1],[1,1],[1,1])

ValueError: only 2 non-keyword arguments accepted

In [4]: a_Mat = np.array([[1,1],[1,1],[1,1]])

In [5]: a_Mat
Out[5]:
array([[1, 1],
[1, 1],
[1, 1]])

In [6]: a_Mat[1:]
Out[6]:
array([[1, 1],
[1, 1]])

In [7]: a_Mat = np.array([[1,1],[2,2],[3,3]])

In [8]: a_Mat
Out[8]:
array([[1, 1],
[2, 2],
[3, 3]])

In [9]: a_Mat[2:]
Out[9]: array([[3, 3]])

In [10]: a_Mat[1:]
Out[10]:
array([[2, 2],
[3, 3]])

In [11]: a_Mat[1:]=['k','k']
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-11-77dcaa96fc0d> in <module>()
----> 1 a_Mat[1:]=['k','k']

ValueError: invalid literal for int() with base 10: 'k'

In [12]: a_Mat[1:]=[6,6]

In [13]: a_Mat
Out[13]:
array([[1, 1],
[6, 6],
[6, 6]])

In [14]: a_Mat[0]=[7,7]

In [15]: a_Mat
Out[15]:
array([[7, 7],
[6, 6],
[6, 6]])

In [16]: a_Mat[1,:]=[9,6]

In [17]: a_Mat
Out[17]:
array([[7, 7],
[9, 6],
[6, 6]])
In [18]: a_Mat[2,1]
Out[18]: 6

In [19]: a_Mat[2,0]
Out[19]: 6

In [20]: a_Mat[2,0]=4

In [21]: a_Mat
Out[21]:
array([[7, 7],
[9, 6],
[4, 6]])