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pythonoverflowrange
Bolster
Bolster

Reputation: 7916

Python: Range() maximum size; dynamic or static?

I'm quite new to python, so I'm doing my usual of going through Project Euler to work out the logical kinks in my head.

Basically, I need the largest list size possible, ie range(1,n), without overflowing.

Any ideas?

Upvotes: 6

Views: 19025

Answers (2)

Devin Jeanpierre
Devin Jeanpierre

Reputation: 95596

Look at get_len_of_range and get_len_of_range_longs in the builtin module source

Summary: You'll get an OverflowError if the list has more elements than can be fit into a signed long. On 32bit Python that's 2**31 - 1, and on 64 bit Python that's 2**63 - 1. Of course, you will get a MemoryError even for values just under that.

Upvotes: 8

Aaron Digulla
Aaron Digulla

Reputation: 328764

The size of your lists is only limited by your memory. Note that, depending on your version of Python, range(1, 9999999999999999) needs only a few bytes of RAM since it always only creates a single element of the virtual list it returns.

If you want to instantiate the list, use list(range(1,n)) (this will copy the virtual list).

Upvotes: 0

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