Steven D'Aprano wrote: > On Sun, 25 Nov 2007 01:38:51 +0100, Hrvoje Niksic wrote: > >> samwyse <[EMAIL PROTECTED]> writes: >> >>> create a hash that maps your keys to themselves, then use the values of >>> that hash as your keys. >> The "atom" function you describe already exists under the name "intern". > > Not really. intern() works very differently, because it can tie itself to > the Python internals. Samwyse's atom() function doesn't, and so has no > purpose. > > > In any case, I'm not sure that intern() actually will solve the OP's > problem, even assuming it is a real and not imaginary problem. According > to the docs, intern()'s purpose is to speed up dictionary lookups, not to > save memory. I suspect that if it does save memory, it will be by > accident. > >>From the docs: > http://docs.python.org/lib/non-essential-built-in-funcs.html
Yes, but it seems that buffer remains with Python 3000. Colin W. > > intern( string) > Enter string in the table of ``interned'' strings and return the interned > string - which is string itself or a copy. Interning strings is useful to > gain a little performance on dictionary lookup - if the keys in a > dictionary are interned, and the lookup key is interned, the key > comparisons (after hashing) can be done by a pointer compare instead of a > string compare. Normally, the names used in Python programs are > automatically interned, and the dictionaries used to hold module, class > or instance attributes have interned keys. Changed in version 2.3: > Interned strings are not immortal (like they used to be in Python 2.2 and > before); you must keep a reference to the return value of intern() around > to benefit from it. > > > Note the words "which is string itself or a copy". It would be ironic if > the OP uses intern to avoid having copies of strings, and ends up with > even more copies than if he didn't bother. > > I guess he'll actually need to measure his memory consumption and see > whether he actually has a memory problem or not, right? > > -- http://mail.python.org/mailman/listinfo/python-list
