Python 3.5 has an explicit operator @ for the dot product,
so you can write
a = A @ B
instead of
a = numpy.dot(A,B)
import numpy
result = numpy.dot( numpy.array(A)[:,0], B)
http://docs.scipy.org/doc/numpy/reference/
If you want to do it without numpy, try
sum( [a[i][0]*b[i] for i in range(len(b))] )