a.py

```
import math
y = [] # empty list used as empty dynamic aray
print y # to visualize what we have before
for x in xrange(100):
y.append(math.sin(x * 20))
print y # what is inside after
print '-' * 70
# The alternative approach to simulate better the array. The list
# of 100 elements is created first. Then the "normal" indexing
# can be used to access and modify the elements.
y = [0] * 100
print y # to visualize what we have before
for x in xrange(100):
y[x] = math.sin(x * 20)
print y # what is inside after
```