python - append usage

E.g:

a=[1,2,3]
 
a.append(5)

In this case, the results of [1, 2, 3, 5]

a=[1,2,3]
 
a.append([5])

In this case, the results of [1, 2, 3, [5]]

The result is no longer an array, but the list

 

Generate a multidimensional array using append:

import numpy as np
 
a=[] 
 
for i in range(5): 
 
  a.append([])
 
  for j in range(5): 
 
    a[i].append(i)

　　The results are as follows:

[[0, 0, 0, 0, 0],
 
 [1, 1, 1, 1, 1],
 
 [2, 2, 2, 2, 2],
 
 [3, 3, 3, 3, 3],
 
 [4, 4, 4, 4, 4]]

　　append () function in the list of python is a good use of