Question

When I try to assign the array from array.array module as follows:

a = array('f')

a[0] = 2.2

I get array assignment out of range, so basically I have to allocate some dummy values and size in the first statement itself like a = array('f',[0]*20). Is that right?

Answer 1

That happens with list also:

>>> L = []
>>> L[0] = 'a'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: list assignment index out of range

Basically the [] syntax requires that the index is valid. It cannot be used to add elements.

The array.array class support most list methods, you can use those to add elements after creation.