Numpy array syntax inconsistent to the degree it can be considered broken. For instance, to take elements number 4,3,2 of an array in Python, one writes A[3:0:-1], but for the elements 3,2,1 one has to write A[2::-1], because someone decided that making A[-1] refer to the last element of an array is "intuitive", and so A[2:-1:-1] will return empty slice.

Now if you want to use array comprehensions, the first case looks similar: [A[k] for k in range(3,0,-1)] but the second now has to be [A[k] for k in range(2,-1,-1)].

Further, for some reason, array and matrix are different types and one has to convert back and forth between them.