Python中的 numpy.tri()

numpy.tri(R, C = None, k = 0, dtype = 'float') ：创建一个数组，在给定的对角线（大约 k）处及下方为 1，其他地方为 0。
参数 ：

R     : Number of rows
C     : [optional] Number of columns; By default R = C
k     : [int, optional, 0 by default]
               Diagonal we require; k>0 means diagonal above main diagonal or vice versa.
dtype : [optional, float(byDefault)] Data type of returned array.  

# Python Program illustrating
# numpy.tri method
  
import numpy as geek
  
print("tri with k = 1 : \n",geek.tri(2, 3, 1, dtype = float), "\n")
  
print("tri with main diagonal : \n",geek.tri(3, 5, 0), "\n")
  
print("tri with k = -1 : \n",geek.tri(3, 5, -1), "\n")

输出 ：

tri with k = 1 : 
 [[ 1.  1.  0.]
 [ 1.  1.  1.]] 

tri with main diagonal : 
 [[ 1.  0.  0.  0.  0.]
 [ 1.  1.  0.  0.  0.]
 [ 1.  1.  1.  0.  0.]] 

tri with k = -1 : 
 [[ 0.  0.  0.  0.  0.]
 [ 1.  0.  0.  0.  0.]
 [ 1.  1.  0.  0.  0.]]