lua – 使用“数组样式”表是否比使用“地图样式”表提供更快的

Until Lua 4.0,tables were implemented strictly as hash tables: all pairs were
explicitly stored. Lua 5.0 brought a new algorithm to optimize the use of tables
as arrays: it optimizes pairs with integer keys by not storing the keys and storing the values in an actual array. More precisely,in Lua 5.0,tables are implemented as hybrid data structures: they contain a hash part and an array part.

[…]

This hybrid scheme has two advantages. First,access to values with integer keys is faster because no hashing is needed. Second,and more important,the array part takes roughly half the memory it would take if it were stored in the hash part,because the keys are implicit in the array part but explicit in the hash part. As a consequence,if a table is being used as an array,it performs as an array,as long as its integer keys are dense. Moreover,no memory or time penalty is paid for the hash part,because it does not even exist.

所以,是的,如果你使用Lua 5或更高版本,那么只使用表格作为数组,速度和内存应该存在显着差异.

I doubt the performance difference would matter much,even if it’s called a million times a minute in my main game loop.

在得出与性能相关的任何内容之前,最好先进行基准测试,因为这通常是违反直觉的.对于可读性而言,你可能会对表现感到满意 – 但是要以明智的方式这样做.

如果您可以编写辅助函数来获取相同的数据,也许您不必牺牲可读性：

function X(t)
    return t[1]
end

function Y(t)
    return t[2]
end

local pos = { 8,1 }
print(X(pos))