day1-5-Numpy数组形状
In [2]:
import numpy as np
array1 = np.arange(10)
array1
Out[2]:
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
In [3]:
array1.shape
Out[3]:
(10,)
In [7]:
array1.shape=2,5 #将array1分成2维数组
array1
Out[7]:
array([[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]])
In [8]:
array1.reshape(1,10) #将array1数组分成1维数组一组有10个,大小不能改变
Out[8]:
array([[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]])
In [9]:
array1 = np.arange(10)
array1.shape
Out[9]:
(10,)
In [10]:
array1 = array1[np.newaxis,:]
array1.shape
Out[10]:
(1, 10)
In [11]:
array1 = np.arange(10)
array1.shape
Out[11]:
(10,)
In [12]:
array1 = array1[:,np.newaxis]
array1.shape
Out[12]:
(10, 1)
In [13]:
array1 = array1[:,np.newaxis,np.newaxis]
array1.shape
Out[13]:
(10, 1, 1, 1)
In [14]:
array1 = array1.squeeze()
array1.shape
Out[14]:
(10,)
In [16]:
array1.shape = 2,5
array1
Out[16]:
array([[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]])
In [17]:
array1.transpose() #将数组数组维度互换
Out[17]:
array([[0, 5],
[1, 6],
[2, 7],
[3, 8],
[4, 9]])
In [18]:
array1.T
Out[18]:
array([[0, 5],
[1, 6],
[2, 7],
[3, 8],
[4, 9]])
In [19]:
array1
Out[19]:
array([[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]])
In [20]:
a = np.array([[123,456,678],[3214,456,134]])
a
Out[20]:
array([[ 123, 456, 678],
[3214, 456, 134]])
In [22]:
b=np.array([[111,222,333],[999,888,777]])
b
Out[22]:
array([[111, 222, 333],
[999, 888, 777]])
In [23]:
c = np.concatenate((a,b)) #将a,b数组连接
c
Out[23]:
array([[ 123, 456, 678],
[3214, 456, 134],
[ 111, 222, 333],
[ 999, 888, 777]])
In [24]:
c = np.concatenate((a,b),axis = 0) #按0维组合
c
Out[24]:
array([[ 123, 456, 678],
[3214, 456, 134],
[ 111, 222, 333],
[ 999, 888, 777]])
In [25]:
c = np.concatenate((a,b),axis = 1) #按1维组合
c
Out[25]:
array([[ 123, 456, 678, 111, 222, 333],
[3214, 456, 134, 999, 888, 777]])
In [26]:
c.shape
Out[26]:
(2, 6)
In [28]:
np.vstack((a,b)) #垂直组合
Out[28]:
array([[ 123, 456, 678],
[3214, 456, 134],
[ 111, 222, 333],
[ 999, 888, 777]])
In [29]:
np.hstack((a,b)) #水平组合
Out[29]:
array([[ 123, 456, 678, 111, 222, 333],
[3214, 456, 134, 999, 888, 777]])
In [30]:
a
Out[30]:
array([[ 123, 456, 678],
[3214, 456, 134]])
In [32]:
a.flatten() #将数组改为1维
Out[32]:
array([ 123, 456, 678, 3214, 456, 134])
In [ ]:

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