On 2019-06-25 04:18, Brian Milby via use-livecode wrote:
My guess is that it has to do with the copy on write property of
arrays. If you used your method it may force an actual duplication.
The existing method just passes a pointer effectively. I could be
totally wrong though.
On Jun 24, 2019, 10:11 PM -0400, Mark Wieder via use-livecode
<use-livecode@lists.runrev.com>, wrote:
> put xArray[item 1 of pPath] into tSubArray
> delete variable xArray[item 1 of pPath]
> put tSubArray into xArray[pKey]
Interesting. Wouldn't it be faster to do
put xArray[item 1 of pPath] into xArray[pKey]
delete variable xArray[item 1 of pPath]
i.e., why the extra copy?
In terms of copies there are none happening in either case - only xArray
is being mutated - and referencing counting means that the 'puts' are
all free.
The first will be 'on average' marginally more efficient but that's
because of the number of keys...
In method (1) the number of keys goes from N -> N - 1 -> N
In method (2) the number of keys goes from N -> N + 1 -> N
Its much more likely that adding a key will cause the engine to have to
extend the internal vector of key-value pairs it uses to store the array
mapping then removing a key will cause it to shrink it - also expansion
is 'on average' slower than shrinking.
Warmest Regards,
Mark.
--
Mark Waddingham ~ m...@livecode.com ~ http://www.livecode.com/
LiveCode: Everyone can create apps
_______________________________________________
use-livecode mailing list
use-livecode@lists.runrev.com
Please visit this url to subscribe, unsubscribe and manage your subscription
preferences:
http://lists.runrev.com/mailman/listinfo/use-livecode
