使用numpy，如何生成一个数组，其中每个索引的值是从0到第二个数组中相同索引的值的总和？

Question

Given a numpy array a=[3,5,7]

How can I efficiently generate a second array b, where b[i] = numpy.Sum(a[0:i]?

I've looked through the numpy docs but the solution isn't jumping out at me...

The expected output would be b=[3,8,15]

Any ideas will be gratefully received!!!

Thanks,

Doug

Answer 1

You seem to want the cumsum function from numpy here:

a=np.array([3,5,7])

In [1]: np.cumsum(a)
Out[1]: array([ 3,  8, 15], dtype=int32)