Hi, I read a code snippet, in which object w_A is: w_A Out[48]: array([ 0.10708809, 0.94933575, 0.8412686 , 0.03280939, 0.59985308]) Then, I don't know what is '[: ' below: vs_A = w_A[:, None] * xs I don't find the answer after searching around Could you explain above code to me? Thanks,