How to obtain vale count from table?

Lur · 01-20-12, 07:09 AM

Hello everyone.
I got a small problem writing a little addon.

There is GetGossipAvailableQuests() frunction

Let's imagine we are talking with a NPC with 3 available quests. So if I want to iterate all returned quests, I write something like:

Code:

local q = {GetGossipAvailableQuests()} 
for i=1, #q, 5 do 
   print(q[i])
end

The question is:
1. why #q returns correct count while documentation says that next after first nil value index are returned even if there are another non-nil values
2. why select("#", q) doesn't work correct then?

Thanks a lot!

Rilgamon · 01-20-12, 07:56 AM

Edit: Forget my answer

Torhal · 01-20-12, 08:42 AM

1: Any nil values are ignored in table construction. If, after construction, you explicitly set a value to nil, the rule you spoke of would take effect.

2: "If index is a number, returns all arguments after argument number index. Otherwise, index must be the string "#", and select returns the total number of extra arguments it received." If you are assigning the return value of select() to a single variable, it stands to reason that the rest of the return values would be discarded.

Lur · 01-20-12, 10:16 AM

Originally Posted by Torhal

1: Any nil values are ignored in table construction. If, after construction, you explicitly set a value to nil, the rule you spoke of would take effect.

Don't you mind to provide a link? I can't found anything like that in 5.1 reference ...

2: "If index is a number, returns all arguments after argument number index. Otherwise, index must be the string "#", and select returns the total number of extra arguments it received." If you are assigning the return value of select() to a single variable, it stands to reason that the rest of the return values would be discarded.

So, select("#" doesn't return the pair count in the table? It's just returns something like

Code:

local l = {[1]=1,[2]=2,[3]=3}
select("#", l)  -- = 1
select("#", a,b,c)  -- = 3

Phanx · 01-20-12, 07:19 PM

Originally Posted by Lur

So, select("#" doesn't return the pair count in the table? It's just returns something like

Code:

local l = {[1]=1,[2]=2,[3]=3}
select("#", l)  -- = 1
select("#", a,b,c)  -- = 3

Yes. Also:

Code:

local t = { [1] = "first", [2] = "second", [3] = "third" }
#t --> 3

t["foo"] = "bar"
#t --> 3 -- non-indexed table entries don't count

t[2] = nil
#t --> 1 -- because you created a gap

Lur · 01-22-12, 01:48 AM

Originally Posted by Phanx

Yes. Also:

Thanks a lot. But why

Code:

local t1 =  {1,2, nil, "wwew", nil,3} -- #t1 = 6
local t2 = { 1,2, nil, "wwew", 3, nil }  -- #t2 = 2

What's wrong with all of that? Why tables with a nil as the last value are truncated to the first nil occurrence while with any non-nil end are counted correct?

Xubera · 01-28-12, 04:52 AM

Why not try it a different way.

Code:

local q={GetGossipAvailableQuests()}
for i=1, GetNumGossipAvailableQuests() do
    print(1 + ((i-1)*5), q[1 + ((i-1)*5)])
end