数组和矩阵计算的区别。通过getA()可以把矩阵转化为数组
#
from numpy import*
w = ones((3, 1)) #创建数组
weights = mat(w) #转换为numpy矩阵
s = weights.getA() #将numpy矩阵转换为数组
x = arange(-3.0, 3.0, 0.1)
y1 = (-weights[0] - weights[1]*x)/weights[2] #矩阵
y2 = (s[0] - s[1] *x)/s[2] #数组
print(len(y1))
print(y1)
print(len(y2))
print(y2)
1
[[ 2.00000000e+00 1.90000000e+00 1.80000000e+00 1.70000000e+00
1.60000000e+00 1.50000000e+00 1.40000000e+00 1.30000000e+00
1.20000000e+00 1.10000000e+00 1.00000000e+00 9.00000000e-01
8.00000000e-01 7.00000000e-01 6.00000000e-01 5.00000000e-01
4.00000000e-01 3.00000000e-01 2.00000000e-01 1.00000000e-01
-1.77635684e-15 -1.00000000e-01 -2.00000000e-01 -3.00000000e-01
-4.00000000e-01 -5.00000000e-01 -6.00000000e-01 -7.00000000e-01
-8.00000000e-01 -9.00000000e-01 -1.00000000e+00 -1.10000000e+00
-1.20000000e+00 -1.30000000e+00 -1.40000000e+00 -1.50000000e+00
-1.60000000e+00 -1.70000000e+00 -1.80000000e+00 -1.90000000e+00
-2.00000000e+00 -2.10000000e+00 -2.20000000e+00 -2.30000000e+00
-2.40000000e+00 -2.50000000e+00 -2.60000000e+00 -2.70000000e+00
-2.80000000e+00 -2.90000000e+00 -3.00000000e+00 -3.10000000e+00
-3.20000000e+00 -3.30000000e+00 -3.40000000e+00 -3.50000000e+00
-3.60000000e+00 -3.70000000e+00 -3.80000000e+00 -3.90000000e+00]]
60
[ 4.00000000e+00 3.90000000e+00 3.80000000e+00 3.70000000e+00
3.60000000e+00 3.50000000e+00 3.40000000e+00 3.30000000e+00
3.20000000e+00 3.10000000e+00 3.00000000e+00 2.90000000e+00
2.80000000e+00 2.70000000e+00 2.60000000e+00 2.50000000e+00
2.40000000e+00 2.30000000e+00 2.20000000e+00 2.10000000e+00
2.00000000e+00 1.90000000e+00 1.80000000e+00 1.70000000e+00
1.60000000e+00 1.50000000e+00 1.40000000e+00 1.30000000e+00
1.20000000e+00 1.10000000e+00 1.00000000e+00 9.00000000e-01
8.00000000e-01 7.00000000e-01 6.00000000e-01 5.00000000e-01
4.00000000e-01 3.00000000e-01 2.00000000e-01 1.00000000e-01
-3.55271368e-15 -1.00000000e-01 -2.00000000e-01 -3.00000000e-01
-4.00000000e-01 -5.00000000e-01 -6.00000000e-01 -7.00000000e-01
-8.00000000e-01 -9.00000000e-01 -1.00000000e+00 -1.10000000e+00
-1.20000000e+00 -1.30000000e+00 -1.40000000e+00 -1.50000000e+00
-1.60000000e+00 -1.70000000e+00 -1.80000000e+00 -1.90000000e+00]
#
from numpy import*
a=[[1,2,3],[4,5,6]]
print(a)
print(array(a))
print(mat(a))
print(array(a[1]))
print(array(a)[1].shape)
print(mat(a)[1].shape)
[[1, 2, 3], [4, 5, 6]]
[[1 2 3]
[4 5 6]]
[[1 2 3]
[4 5 6]]
[4 5 6]
(3,)
(1, 3)