On 12/2/2011 4:53 AM, Hrvoje Niksic wrote:
Chris Angelico<ros...@gmail.com> writes:
The hash can grow with (k,v) pairs accumulated in the run time.
An auto memory management mechanism is required for a hash of a non-fixed size
of (k,v) pairs.
That's a hash table
In many contexts "hash table" is shortened to "hash" when there is no
ambiguity. This is especially popular among Perl programmers where the
equivalent of dict is called a hash.
Although strictly speaking, isn't that "Python dicts are implemented
as hash tables in CPython"? Or is the hashtable implementation
mandated?
It's pretty much mandated because of the __hash__ protocol.
Lib Ref 4.8. Mapping Types — dict
"A mapping object maps hashable values to arbitrary objects."
This does not say that the mapping has to *use* the hash value ;-).
Even if it does, it could use a tree structure instead of a hash table.
But hash tables seem to work well for general purposes,
"Mappings are mutable objects."
(This would change if a frozendict were added.)
especially when additions and deletions are needed.
--
Terry Jan Reedy
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