How to make an empty array of array's in python

Question

I wrote a code to do some kind of algorithm. For this I need a array of array's like: d = [[1,4,5], [0,3,6,1], [7,3]]. I made an randomizer to get random data to work with. For this randomizer i need to start with an empty list like: d = [[][][]] This works well, but when i change the number of rows in my algorithm i have to change this by hand. Is there a way to change the number automatically? I tried:

d = []*10

and

d = []
for i in range(1, n+1):
    d[i] = []

but both do not work.