python中矩阵运算总结

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1.矩阵的初始化

import numpy as np

（1）.创建全X的矩阵

myzero = np.zeros([3,5]) #全0的矩阵

（2）随机矩阵

myrand = np.random.rand(3,4)

(3) 单位阵

myeye = np.eye(3)

(4)矩阵运算

from numpy import *

加减乘直接“+” “ -” “*”

（5）矩阵元素和

mymatrix = mat([[1,2,3],[4,5,6],[7,8,9]])
print (sum(mymatrix))

(6) 矩阵元素积

multiply

(7)N次幂

from numpy import *
a = mat ( [ [1,2,3],[4,5,6],[7,8,9] ] )
print (power(a,2))

（8）矩阵转置

from numpy import *
a = mat ( [ [1,2,3],[4,5,6],[7,8,9] ] )
print (a.T)

（9）其他操作

from numpy import *
a = mat ( [ [1,2,3],[4,5,6],[7,8,9] ] )
[c,d] = shape(a)
print ("矩阵行列数：",c,d)

e = a [0] #按行切片

f = a.T[0] #按列切片

g = a.copy() #复制

#比较直接“<” “>” "=" 返回的是bool型