To initialize a large list with same value (all items having same value), the following syntax can be used.
a = [val] * num_items
Example
a = [0]*20 print a a = [None]*20 print a
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] [None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None]
Env: Python 2.7.18