Re: how to work with tables with holes
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- Subject: Re: how to work with tables with holes
- From: Dirk Laurie <dirk.laurie@...>
- Date: 2013年9月27日 10:02:27 +0200
2013年9月27日 Rafis Ganeyev <rafisganeyev@gmail.com>:
> Another gotcha (Lua so hard to use :( )
It becomes easier as you go along, particularly if you spend
some time reading the manual and "Programming in Lua".
> If you are deleting elements from collection using *pairs()*, you can't
> delete element with *table.remove()*, you must delete only element that
> *pairs()* pointed to you:
>
> local t = setmetatable({ 1, 2 }, mt)
> for i, obj in pairs(t) do
> obj:teardown()
> table.remove(t)
> end
> print(#t) -- prints 1
>
> This will not delete element t[1].
Of course it won't. You have programmed the following:
i=1
while true do
if t[i] does not exist, break
remove t[i] and move down the others
i=i+1
end
You can delete any element you like, but you must remember
that 'remove' changes the association between elements and
keys.