numpy 矩阵操作

import numpy as np
a = np.random.randint(0,10,[5,5])
print(a)
# c = np.triu(a,0)  #上三角
# print(c)
# d = np.tril(a,0) # 下三角
# print(d)

# 寻找上三角形的位置
up = np.triu(a,1)
up_bool = a==up
up_palce = np.argwhere(up_bool==True)
for i,j in up_palce:
    if i<=j:  # 下三角就是x大于等于y，他两想相反。
        a[i,j] = 66
print(a)


# 寻找对角线的位置
c = np.diag(a,0)
print(c)
s = a==c
index = np.argwhere(s==True)
print(index)
for x,y in index:
    if x==y:
        a[x,y] =0
print(a)