How Big can a Python List Get

Question

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

User · Answer

As the Python documentation says   sys maxsize     The largest positive integer supported by the platform   s Py ssize t type  and thus the maximum size lists  strings  dicts  and many other containers can have    In my computer  Linux x86 64     gt  gt  gt  import sys  gt  gt  gt  print sys maxsize 9223372036854775807

User · Answer

It varies for different systems  depends on RAM   The easiest way to find out is  import six six MAXSIZE 9223372036854775807  This gives the max size of list and dict too  as per the documentation

User · Answer

Sure it is OK  Actually you can see for yourself easily   l   range 12000  l   sorted l  reverse True    Running the those lines on my machine took   real    0m0 036s user    0m0 024s sys  0m0 004s   But sure as everyone else said  The larger the array the slower the operations will be

User · Answer

I d say you re only limited by the total amount of RAM available   Obviously the larger the array the longer operations on it will take

User · Answer

Performance characteristics for lists are described on Effbot   Python lists are actually implemented as vector for fast random access  so the container will basically hold as many items as there is space for in memory   You need space for pointers contained in the list as well as space in memory for the object s  being pointed to    Appending is O 1   amortized constant complexity   however  inserting into deleting from the middle of the sequence will require an O n   linear complexity  reordering  which will get slower as the number of elements in your list   Your sorting question is more nuanced  since the comparison operation can take an unbounded amount of time  If you re performing really slow comparisons  it will take a long time  though it s no fault of Python s list data type   Reversal just takes the amount of time it required to swap all the pointers in the list  necessarily O n   linear complexity   since you touch each pointer once

User · Answer

12000 elements is nothing in Python    and actually the number of elements can go as far as the Python interpreter has memory on your system

User · Answer

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  gt  gt 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

User · Answer

In casual code I ve created lists with millions of elements  I believe that Python s implementation of lists are only bound by the amount of memory on your system    In addition  the list methods   functions should continue to work despite the size of the list    If you care about performance  it might be worthwhile to look into a library such as NumPy

User · Answer

I got this from here on a x64 bit system  Python 3 7 0b5  v3 7 0b5 abb8802389  May 31 2018  01 54 01   MSC v 1913 64 bit  AMD64   on win32

User · Answer

There is no limitation of list number   The main reason which causes your error is the RAM   Please upgrade your memory size

[python] How Big can a Python List Get?

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