[Python-Dev] Re: Re: Caching objects in memory

Terry Reedy tjreedy at udel.edu
Mon Apr 25 23:13:05 CEST 2005


But for *immutable* objects (like numbers, strings and tuples) the
implementation is free to use caching. In practice, I believe ints
between -5 and 100 are cached, and 1-character strings are often
cached (but not always).

Hope this helps! I would think this is in the docs somewhere but
probably not in a place where one would ever think to look...

I am sure that the fact that immutables *may* be cached is in the ref 
manual, but I have been under the impression that the private, *mutable* 
specifics for CPython are intentionally omitted so that people will not 
think of them as either fixed or as part of the language/library.

I have previously suggested that there be a separate doc for CPython 
implementation details like this that some people want but which are not 
part of the language or library definition.

Terry J. Reedy

More information about the Python-Dev mailing list