How Big can a Python List Get?

python list size
Devoted picture Devoted · May 13, 2009 · Viewed 176.2k times · Source

In Python, how big can a list get? I need a list of about 12000 elements. Will I still be able to run list methods such as sorting, etc?

Answer

Unknown picture Unknown · May 13, 2009

According to the source code, the maximum size of a list is PY_SSIZE_T_MAX/sizeof(PyObject*).

PY_SSIZE_T_MAX is defined in pyport.h to be ((size_t) -1)>>1

On a regular 32bit system, this is (4294967295 / 2) / 4 or 536870912.

Therefore the maximum size of a python list on a 32 bit system is 536,870,912 elements.

As long as the number of elements you have is equal or below this, all list functions should operate correctly.

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