Re: ipairs in Lua 5.3.0-alpha

["Joseph Manning" <manning@...>]

On 2014-Aug-14 (Thu) at 03:23 (+0200), Jan Behrens wrote:

>> If Lua's built-in O(log n) length operator is really that fast, then
>> caching the length might not make sense in my case.

Jan,

   At one stage, I was also concerned about evaluating #t several times
   for the same table, and considered caching this value for efficiency,
   even at the cost of a slight code obfuscation.

   So I ran a simple benchmark.

   For a table t with 10,000 elements, I found that #t can be calculated
   1,000,000 times in under 0.1 seconds.  And on a 6-year-old "netbook".

   So you probably need not worry about re-evaluating #t.  It's fast.

Joseph

PS: the above was with Lua 5.2

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Joseph Manning / Computer Science / UCC Cork Ireland / manning@cs.ucc.ie
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