Numpy

NumPy（Python拓展程序库） 最重要的一个特点是其 N 维数组对象 ndarray，其下有array函数

numpy.array(object, dtype = None, copy = True, order = None, subok = False, ndmin = 0)

https://www.runoob.com/numpy/numpy-array-from-numerical-ranges.html

In [11]: a=np.array([1,2,3])
In [12]: a.reshape(3,1) #3*1,维度调节
Out[12]: 
array([[1],
       [2],
       [3]])

In [1]: import numpy as np
In [2]: a=np.arange(10)
In [3]: s=slice(2,7,2) #切片的使用方法
In [4]: print (a[s])
[2 4 6]

In [1]: import numpy as np
In [3]: a=np.array([[1,2,3],[4,5,6],[7,8,9]])
In [4]: print (a[...,1]) #第二列
[2 5 8]
In [5]: print(a[2,...]) #第二行   a[r,c]
[7 8 9]
In [7]: print (a[0,0],a[1,1],a[2,2]) #获取对应位置的数据
1 5 9
In [8]: print (a[[0,1,2],[0,1,2]]) #整数索引，将角标分开来索引
[1 5 9]