2-1Numpy概述

In [1]:

import numpy as np

In [2]:

array=[1,2,3,4,5]
array+1#没定义成numpy.ndarray类型是不能直接操做的

 

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-2-bae0c13eab71> in <module>()
      1 array=[1,2,3,4,5]
----> 2array+1

TypeError: can only concatenate list (not "int") to list

In [3]:

array=np.array([1,2,3,4,5])
print(type(array))

 

<class 'numpy.ndarray'>

In [6]:

array2=array+1
array2

Out[6]:

array([4, 5, 6, 7, 8])

In [7]:

array*array2

Out[7]:

array([12, 20, 30, 42, 56])

In [8]:

array[0]

Out[8]:

3

In [9]:

array.shape#数组大小

Out[9]:

(5,)

In [10]:

np.array([[1,2,3],[4,5,6]])

Out[10]:

array([[1, 2, 3],
       [4, 5, 6]])