Numpy矩阵的常用操作

短命女 2023-06-19 09:46 28阅读 0赞

1.  开方
    
        import numpy as np
        B=np.arange(3)
        print(B)
        print(np.exp(B))
        print(np.sqrt(B))
    
    运行结果：  
    ![在这里插入图片描述][20191205164837802.png]
2.  floor向下取整
    
        a=np.floor(10*np.random.random((3,4)))
        print(a)
        print('----')
        # 把矩阵变成向量
        print(a.ravel())
        print('----')
        a.shape=(6,2)
        print(a)
        print('----')
        print(a.T)
    
    运行结果：  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg_size_16_color_FFFFFF_t_70]
3.  水平拼接：
    
        a=np.floor(10*np.random.random((2,2)))
        b=np.floor(10*np.random.random((2,2)))
        print(a)
        print('---')
        print(b)
        print('---')
        print(np.hstack((a,b)))
    
    运行结果：  
    ![在这里插入图片描述][20191205165852828.png]
4.  垂直拼接：
    
        a=np.floor(10*np.random.random((2,2)))
        b=np.floor(10*np.random.random((2,2)))
        print(a)
        print('---')
        print(b)
        print('---')
        print(np.vstack((a,b)))
    
    运行结果：  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg_size_16_color_FFFFFF_t_70 1]
5.  分割:
    
        a=np.floor(10*np.random.random((2,12)))
        print(a)
        print('---')
        print(np.hsplit(a,3))
        print('---')
        print(np.hsplit(a,(3,4)))
        a=np.floor(10*np.random.random((12,2)))
        print('---')
        print(a)
        np.vsplit(a,3)
    
    运行结果：  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg_size_16_color_FFFFFF_t_70 2]

[20191205164837802.png]: https://img-blog.csdnimg.cn/20191205164837802.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191205165152472.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg==,size_16,color_FFFFFF,t_70
[20191205165852828.png]: https://img-blog.csdnimg.cn/20191205165852828.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20191205165943880.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20191205170700351.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjI2MDEwMg==,size_16,color_FFFFFF,t_70