OOP help

[MarekkPie]

Completely off topic, but brilliant use of Ming the Merciless.

[Roland_Yonaba]

Kikito, that was epic. Bookmarked that response, I am likely to redirect bunch of people to this.

[Robin]

So I should make a whole new table for the objects to store in?

That's possible, but not necessary (although personally, I prefer to have a separate table for instances, but again: you don't need to).

What you really need is to use ipairs, instead of pairs. Unlike pairs, which goes over all the keys in the table, ipairs only goes over integer keys from 1 to n, which is what you want in this case.

[Zilarrezko]

[quote="Robin"
What you really need is to use ipairs, instead of pairs. Unlike pairs, which goes over all the keys in the table, ipairs only goes over integer keys from 1 to n, which is what you want in this case.[/quote]

Ah! So it skips all the things like metatables and other tables?

[Robin]

Neither pairs nor ipairs does anything with a table's metatable.

If you have this table:

Code: Select all

local t = {}
t[1] = "one"
t[2] = "two"
t[3] = "three"
t["four"] = 4
local five = {five = 5}
t[five] = 5
t[true] = 6

Then

Code: Select all

for i, v in ipairs(t) do
    print(i, v)
end

prints

Code: Select all

1	one
2	two
3	three

in that order.

But

Code: Select all

for k, v in pairs(t) do
    print(k, v)
end

prints

Code: Select all

1	one
2	two
3	three
four	4
table: 0x1067080	5
true	6

but you don't know in which order beforehand.

[Zilarrezko]

so then in which cases do tables get a numerical value when entered?

[Robin]

What do you mean?

[Zilarrezko]

In which cases when you enter a value into a table will it's key be a numerical value such as [1] or [2]? Like table.insert(t,{})?

[ejmr]

In which cases when you enter a value into a table will it's key be a numerical value such as [1] or [2]? Like table.insert(t,{})?

Here are the basics on how table.insert() affects numeric indices.

Code: Select all

local t = { "foo", "bar" }

-- t[1] == "foo"
-- t[2] == "baz"
-- #t   == 2     i.e. The length of the table is two.

table.insert(t, "baz")

-- Now t[3] == "baz"
--
-- The call to table.insert() above is a short-cut for this, which
-- would accomplish the same thing:

table.insert(t, #t + 1, "baz")

-- The optional second argument there is the 'position' where the
-- function should insert the new element.  It defaults to the
-- length of the table plus one.

[Zilarrezko]

HEY HEY! no way, I was looking for something like that. I wanted my main menu console to display the start of the table at the bottom just above the console input display area and work it's way up rather than down. Sweetness. But I think I get a good gist of basics of building basic objects and OOP. The last thing I think I need is a greater understanding of how to use the self parameter, and how to build my system and metatable for the use of "self".That series of information from kikito were very confusing.