Question

I’m having trouble understanding the result of the following statements:

>>> from array import array
>>> array('L',[0xff,0xff,0xff,0xff])
array('L', [255L, 255L, 255L, 255L])


>>> from array import array
>>> array('L','\xff\xff\xff\xff')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: string length not a multiple of item size

Answer 1

You are running this on a 64-bit build of Python, on which array treats type code 'L' as a 64-bit unsigned integer.

>>> array('L','\xff\xff\xff\xff\xff\xff\xff\xff')
array('L', [18446744073709551615L])

The documentation isn’t very clear. All it says is that 'L' is at least four bytes.