Create an empty list in python with certain size

Question

I want to create an empty list (or whatever is the best way) that can hold 10 elements.

After that I want to assign values in that list, for example this is supposed

Answer 1

You can .append(element) to the list, e.g.: s1.append(i). What you are currently trying to do is access an element (s1[i]) that does not exist.

Answer 2

I'm surprised nobody suggest this simple approach to creating a list of empty lists. This is an old thread, but just adding this for completeness. This will create a list of 10 empty lists

x = [[] for i in range(10)]

Answer 3

There are two "quick" methods:

x = length_of_your_list
a = [None]*x
# or
a = [None for _ in xrange(x)]

It appears that [None]*x is faster:

>>> from timeit import timeit
>>> timeit("[None]*100",number=10000)
0.023542165756225586
>>> timeit("[None for _ in xrange(100)]",number=10000)
0.07616496086120605

But if you are ok with a range (e.g. [0,1,2,3,...,x-1]), then range(x) might be fastest:

>>> timeit("range(100)",number=10000)
0.012513160705566406