Fill an array with 1 particular value

Via comprehension:

z1=[0 for x in range(20)]
z1
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

Via built-in repeat:

z2=[0] * 20 

Equal? yes.

z1==z2
True

Which one is faster?

timeit.timeit('z=[0 for x in range(100000)]',number=100)
0.8116392770316452

timeit.timeit('z=[0]*100000',number=100)
0.050275236018933356

The built-in repeat beats comprehension hands down!