吴裕雄--天生自然Numpy库学习笔记：NumPy 高级索引

import numpy as np 

x = np.array([[1,  2],  [3,  4],  [5,  6]])
y = x[[0,1,2],  [0,1,0]]
print (y)

import numpy as np 

x = np.array([[  0,  1,  2],[  3,  4,  5],[  6,  7,  8],[  9,  10,  11]])
print ('我们的数组是：' )
print (x)
print ('\n')
rows = np.array([[0,0],[3,3]])
cols = np.array([[0,2],[0,2]])
y = x[rows,cols]
print  ('这个数组的四个角元素是：')
print (y)

import numpy as np

a = np.array([[1,2,3], [4,5,6],[7,8,9]])
b = a[1:3, 1:3]
c = a[1:3,[1,2]]
d = a[...,1:]
print(b)
print(c)
print(d)

import numpy as np 

x = np.array([[  0,  1,  2],[  3,  4,  5],[  6,  7,  8],[  9,  10,  11]])
print ('我们的数组是：')
print (x)
print ('\n')
# 现在我们会打印出大于 5 的元素
print  ('大于 5 的元素是：')
print (x[x >  5])

import numpy as np 

a = np.array([np.nan,  1,2,np.nan,3,4,5])
print (a[~np.isnan(a)])

import numpy as np 

a = np.array([1,  2+6j,  5,  3.5+5j])
print (a[np.iscomplex(a)])

import numpy as np 

x=np.arange(32).reshape((8,4))
print (x[[4,2,1,7]])

x=np.arange(32).reshape((8,4))
print (x[[-4,-2,-1,-7]])

import numpy as np 

x=np.arange(32).reshape((8,4))
print (x[np.ix_([1,5,7,2],[0,3,1,2])])