How to declare array of zeros in python (or an array of a certain size) [duplicate]

Question

buckets = [0] * 100

Careful - this technique doesn't generalize to multidimensional arrays or lists of lists. Which leads to the List of lists changes reflected across sublists unexpectedly problem

Just for completeness: To declare a multidimensional list of zeros in python you have to use a list comprehension like this:

buckets = [[0 for col in range(5)] for row in range(10)]

to avoid reference sharing between the rows.

This looks more clumsy than chester1000's code, but is essential if the values are supposed to be changed later. See the Python FAQ for more details.

You can multiply a list by an integer n to repeat the list n times:

buckets = [0] * 100

Use this:

bucket = [None] * 100
for i in range(100):
    bucket[i] = [None] * 100

OR

w, h = 100, 100
bucket = [[None] * w for i in range(h)]

Both of them will output proper empty multidimensional bucket list 100x100