来源于github上numpy-100，本人当做熟悉numpy
链接：numpy-100
1. Import the numpy package under the name np (★☆☆)
import numpy as np
2. Print the numpy version and the configuration (★☆☆)
print(np.__version__)
np.show_config()
3. Create a null vector of size 10 (★☆☆)
l = np.zeros(10)
4. How to find the memory size of any array (★☆☆)
l = np.zeros((2,4))
print("%d bytes" %(l.size * l.itemsize))
5. How to get the documentation of the numpy add function from the command line?
import numpy as np
np.info(np.add)
10. Find indices of non-zero elements from [1,2,0,0,4,0]
nz = np.nonzero(1,2,0,0,4,0)
print(nz)
11. Create a 3x3 identity matrix
z = np.eye(3)
pirnt(z)
20. Consider a (6,7,8) shape array, what is the index (x,y,z) of the 100th element?
z = np.unravel_index(99, (6,7,8))
(1,5,3)