# 向量運算範例

``````>>> xx = x * x
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: can't multiply sequence by non-int of type 'list'
>>> xx = dot(x,x)
>>> xx
91
>>> ixx = inner(x,x)
>>> ixxx
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'ixxx' is not defined
>>> ixx
91
>>> vxx = vdot(x,x)
>>> vxx
91
>>> outer(x,x)
array([[ 1,  2,  3,  4,  5,  6],
[ 2,  4,  6,  8, 10, 12],
[ 3,  6,  9, 12, 15, 18],
[ 4,  8, 12, 16, 20, 24],
[ 5, 10, 15, 20, 25, 30],
[ 6, 12, 18, 24, 30, 36]])
>>> y = 2:7
File "<stdin>", line 1
y = 2:7
^
SyntaxError: invalid syntax
>>> a = array([1,2,3,4])
>>> b = array([5,6,7,8])
>>> c = arange(1, 5, 0.1)
>>> c
array([ 1. ,  1.1,  1.2,  1.3,  1.4,  1.5,  1.6,  1.7,  1.8,  1.9,  2. ,
2.1,  2.2,  2.3,  2.4,  2.5,  2.6,  2.7,  2.8,  2.9,  3. ,  3.1,
3.2,  3.3,  3.4,  3.5,  3.6,  3.7,  3.8,  3.9,  4. ,  4.1,  4.2,
4.3,  4.4,  4.5,  4.6,  4.7,  4.8,  4.9])
>>> d = linspace(1,5,10)
>>> d
array([ 1.        ,  1.44444444,  1.88888889,  2.33333333,  2.77777778,
3.22222222,  3.66666667,  4.11111111,  4.55555556,  5.        ])
>>> e = logspace(1, 100, num=10)
>>> e
array([  1.00000000e+001,   1.00000000e+012,   1.00000000e+023,
1.00000000e+034,   1.00000000e+045,   1.00000000e+056,
1.00000000e+067,   1.00000000e+078,   1.00000000e+089,
1.00000000e+100])
array([ 6,  8, 10, 12])
>>> mean(a)
2.5
>>> mean(b)
6.5
>>> x=array([1,2,3,4])
>>> sub(a,b)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'sub' is not defined
>>> substract(a,b)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'substract' is not defined
>>> subtract(a,b)
array([-4, -4, -4, -4])
>>> multiply(a,b)
array([ 5, 12, 21, 32])
>>> divide(a,b)
array([0, 0, 0, 0])
>>> divide(b,a)
array([5, 3, 2, 2])
>>> true_divide(b,a)
array([ 5.        ,  3.        ,  2.33333333,  2.        ])
>>>```
```