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On 06/07/13 13:05, Tim Hill wrote:

Even with that explicit length, you can not have a nil inside a string. That would not make any sense. After all, a string is a array of char! :)

What I would find silly is the following:

 --compute the sum of an array:
local sum=0
for i=1, #a do
    if a[i] then sum=sum+a[i]

An array is a very regular structure. This allows for compact agorithms. Having holes in it defeats this. If it has holes, it is not an array, it's a dictionary, and you use other algorithms.

On Jul 6, 2013, at 5:20 AM, Rena <> wrote:

It does seem awfully strange to me: Lua's strings can contain any byte, because they store the length separately from the string data. This is generally considered a good thing, especially compared to C strings - it takes length lookup from O(n) to O(1) and allows them to contain arbitrary binary data. Yet Lua's arrays don't have this same feature, and instead use the C-string method of a magic terminating value that can't appear anywhere in the array, which limits what they can store. (Though I assume length lookup is still O(1) in this case!) And as a "bonus" it makes the # operator's behaviour somewhat strange as well - not always very reliable or useful, and apparently rather confusing to some people.