At 11:41 AM +0100 5/18/06, Andrew Brampton wrote:
Hi,
In the past few weeks I've found the need for a hash table and a
container that gives me O(log) search efficiency. Now I'm aware I
can use associative arrays for my hash table, but I wanted to ensure
efficiency. For my O(log) container I ended up using a sorted array,
and a binary search (which I had to write).
Now I thought common data structures, and algorithms, like these,
and many others such as Binary Trees, Red/Black Trees and sorting
algorithms and so on would be a useful addition to PHP, or more
specifically PEAR, however I was unable to find any previous classes
that provided these structures.
So I figured I would make a set of containers and algorithms that
could be used in a generic way , and hopefully put this code into
PEAR. But before I start making nice PEAR code, I wanted to ask why
nothing like this already exists? Is it because everyone has been to
lazy until now, or is there a real reason that I'm missing that has
made such structures pointless.
thanks for any comments/replies
Andrew
Andrew:
I know what you are talking about, I wrote a splay binary-tree demo, see:
http://www.sperling.com/freeware.php
I've often wondered if there are algorithms like that in php buried somewhere.
However, binary-trees are for searching and I use MySQL for that. I
don't know specifically how MySQL preforms searches. I had hoped that
somewhere one could set a bit and change the algorithms, but I
haven't been able to find any references that allow that.
In any event, the size of the things I work with (<50k items) are so
small that it really doesn't matter for me -- and I don't know at
what size where it starts to be a problem for others.
So, if I was to take my previous code and port it over to php, I
would most certainly test it against MySQL for performance before
spending too much time providing something that doesn't significantly
improve the status-quo.
tedd
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