lua检测表中是否有某个值,如何检查表是否包含Lua中的元素?

Is there a method for checking if a table contains a value ? I have my own (naive) function, but I was wondering if something "official" exists for that ? Or something more efficient...

function table.contains(table, element)

for _, value in pairs(table) do

if value == element then

return true

end

end

return false

end

By the way, the main reason I'm using this functions is to use tables as sets, ie with no duplicate elements. Is there something else I could use ?

解决方案

You can put the values as the table's keys. For example:

function addToSet(set, key)

set[key] = true

end

function removeFromSet(set, key)

set[key] = nil

end

function setContains(set, key)

return set[key] ~= nil

end

There's a more fully-featured example here.