np.cumsum() 函数的解释

    def cumsum(self, axis=None, dtype=None, out=None): 
        """
        a.cumsum(axis=None, dtype=None, out=None)
        
            Return the cumulative sum of the elements along the given axis.
        
            Refer to `numpy.cumsum` for full documentation.
        
            See Also
            --------
            numpy.cumsum : equivalent function
        """
        pass

        返回给定轴的累积和。即按照 axis 轴进行累积求和，输出值中后一个数是前面所有数加上自己本身的和。

例如：

import numpy as np
a = np.asarray([[1, 2, 3],
                [4, 5, 6],
                [7, 8, 9]])
b = a.cumsum(axis=0)
print("b的值：n", b)
c = a.cumsum(axis=1)
print("c的值：n", c)

输出：

D:Anaconda3python.exe "D:/0_me_python/Jupyter Notebook/code/02.py"
b的值：
 [[ 1  2  3]
 [ 5  7  9]
 [12 15 18]]
c的值：
 [[ 1  3  6]
 [ 4  9 15]
 [ 7 15 24]]

Process finished with exit code 0