> Could someone help me in understanding what 64-bit python means? While Chris' answer is correct, it doesn't show the consequences of using a 64-bit Python. Primarily, these are: - strings, Unicode objects, lists, dicts, and tuples can have more than 2**31 elements. - you can load 64-bit DLLs into the Python process, and 64-bit applications (such as a 64-bit Apache or IIS process) can load the Python interpreter into their address spaces. - you need a 64-bit operating system to run Python
The first item is only relevant if a) you have that much data that you want to put into a single container, and b) you have that much memory to keep the entire container in memory. For a list with 2**31 elements, you need 16GiB of memory to represent the list alone, not counting the actual data (e.g. for a list of 2**31 Nones). For a dict, you need more than 48GiB for the dict alone. For a byte string, 2GiB are enough to get past the 2**31 elements boundary. I just noticed that this description is not completely correct: in a 32-bit process, the upper size of collections is actually smaller than 2**31. For a list, you can have only up to 2**30 elements in the list; on many operating systems, only 2**29. For a dict, the maximum number of elements is even smaller, around 250 millions. So you would need a 64-bit Python already to get past these boundaries. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
