Lua编程语言是什么？有什么特点和用途？

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我已经看到了这角儿的色彩。

我已经看到角色’#’被添加到变量的前面很多在Lua,我只是想知道它是做什么的？我在这里找到了一个例子.

-- sort AIs in currentlevel table.sort(level.ais, function(a,b) return a.y < b.y end) local curAIIndex = 1 local maxAIIndex = #level.ais for i = 1,#currentLevel+maxAIIndex do if level.ais[curAIIndex].y+sprites.monster:getHeight() < currentLevel[i].lowerY then table.insert(currentLevel, i, level.ais[curAIIndex]) curAIIndex = curAIIndex + 1 if curAIIndex > maxAIIndex then break end end end

道歉如果这已经被问到,我已经在互联网上搜索了很多,但我似乎没有找到答案.提前致谢！

那就是 length operator：

The length operator is denoted by the unary operator #. The length of a string is its number of bytes (that is, the usual meaning of string length when each character is one byte).

The length of a table t is defined to be any integer index n such that t[n] is not nil and t[n+1] is nil; moreover, if t[1] is nil, n can be zero. For a regular array, with non-nil values from 1 to a given n, its length is exactly that n, the index of its last value. If the array has “holes” (that is, nil values between other non-nil values), then #t can be any of the indices that directly precedes a nil value (that is, it may consider any such nil value as the end of the array).