Hashtable

[Starquizer]

Finally, I applied patch 1.24. Now, I found the hashtable in the triggers but I don't know what is the a hashtable and how it works. Can someone explain this to me ?

 

[xD.Schurke]

you can compare it to new art of storing data.

I don't know if you use jass or gui but first you have to create a hashtable (1 is enough in most cases) then you cann store data in this hashtable for that you have the first and second key. it's in some way similar to a 2d array

//*********
globals
     hashtable table
endglobals

function //*****
     local unit u = CreateUnit(xxx)
     set table = CreateHashtable()
     call SaveUnitHandle(table,1,1,u)
endfunction

function otherone //****
     local unit u = LoadUnitHandle(table,1,1)
endfunction

 

[Vulcano]

or an example with handles (from timerUtils):

    globals
        private hashtable table
    endglobals

    function SetTimerData takes timer t, integer value returns nothing
        call SaveInteger(table,0, GetHandleId(t), value)
    endfunction

    function GetTimerData takes timer t returns integer
        return LoadInteger(table, 0, GetHandleId(t))
    endfunction

although i don't know why you should need two integer keys

EDIT: you also have to initialise a hashtable:

set table = InitHashtable()

 

[Eleandor]

If you know how gamecache works, hashtable works the same but with integers instead of strings. Handles and strings can be converted to integers by using GetHandleId and StringHash.

 

[Element of Water]

There is no native "CreateHashtable". "InitHashtable" is the correct one.

 

[xD.Schurke]

hm kay didn't looked looked it up :O

 

[Starquizer]

1) Can I use it instead of GameCache to save data from campaign to another ?

2) I have heared some problems (bugs) regarding hashtable and patch 1.24, so what are those problems people keep talking about ?

 

[Element of Water]

1) No

2) No bugs, except minor things people like you don't need to worry about.

 

[Starquizer]

People like me !!! ?

 

[GhostWolf]

As in people that will most likely use hashtables in a basic way and not try to abuse it as much as possible and use bugs and such (most people).

 

[Starquizer]

Truthfully, I don't know how good I can use them ?

 

[Dr Super Good]

Think of them as 2D arrays with no max size and can axcept indexes of any 32 bit number in each dimension (even negative).

Thats not how they work, they are more efficent in some ways but thats how they work as far as you the user are concerned.

 

[Starquizer]

OK, I am new to hashtable. How can I use them as 2D arrays ?

Give me a good illustrated example and I'll be gratefull to you. (+ rep)

 

[syltman]

well yeah, this would really be usefull for us who has never used it before

 

[Slaydon]

since we are on the theme, whats possible to create?

 

[Eleandor]

IMO you should avoid using hashtables directly. Table 3.0 is a library that provides a "better" (in my opinion) interface to hashtables.

 

[GhostWolf]

You do not create anything, they simply store stuff.

http://www.hiveworkshop.com/forums/trigger-gui-editor-tutorials-279/hashtables-and-mui-133407/

 

[Starquizer]

IMO you should avoid using hashtables directly. Table 3.0 is a library that provides a "better" (in my opinion) interface to hashtables.

I know about this table, as EoW showed it to me, but I didn't understand it or how to use it, I was trying to use it in a spell I was trying to make.

 

[Eleandor]

Table is like an array except that it can use handles or strings as indices.

For example:

// Normal arrays
local integer array table
local integer i = 4
set table[4] = 25

// HandleTables:
local HandleTable table = HandleTable.create()
local unit u = CreateUnit(...)
set table[u] = 25
// u is used as index. It's a way to link a number to a handle, in this case linking a number to a unit.

 

[Starquizer]

I don't understand this table in the link Eleandor. All I need is to paste that table in my map and everything is done ?

 

[tml616]

A phone book is a big hashtable that keys a name with a phone number.

 

[Eleandor]

I don't understand this table in the link Eleandor. All I need is to paste that table in my map and everything is done ?

Yes. Copy/Paste it and you'll be able to use Table, HandleTable and StringTable.
The code is documented so I'd say: read it and try to understand it.

The phonebook is a good comparison.

 

[Starquizer]

The code is documented so I'd say: read it and try to understand it.

I'll try and understand though I am not a genious to understand that stuff.

And another question: What line(s) do I need change to change the table to HandleTable or StringTable ?

And thanks so far for your help.

 

[Eleandor]

Nothing, you should be able to use Table, HandleTable and StringTable on default.

 

[Nailgun]

Ugh, im tired of this, Blizzard ruined everything. I can't even use vex's stuff right now...

 

[Zhall]

So... how much more efficient if this really?... than say... storing 304 integer variables in a single array [For current project]

I have a few arrays... So i could store them both in one hashtableh?

(yes it's a tableh Wacom ftw, Southpark ftw... ok im done)

 

[Zeatherann]

ok this tut is a GREAT way to learn about them, that's how i did Tutorial

 

[Element of Water]

So... how much more efficient if this really?... than say... storing 304 integer variables in a single array [For current project]

I have a few arrays... So i could store them both in one hashtableh?

(yes it's a tableh Wacom ftw, Southpark ftw... ok im done)

Hashtables are no more efficient than arrays - in fact they're about 2 times slower due to taking two indeces. The advantage with hashtables is their infinite index size, so you can "attach" data to units, timers, etc, by using their "handle id" as an index.

 

[Dr Super Good]

They are about 2 times slower than simlar array systems doing a specific task. They are more than 2 times slower for just array lookup.

 

[Element of Water]

Ok, my bad.

 

[Ciebron]

Think on hashtables like this

2D array

Integer['index1']['index2'] = 'value'

Hashtable

SaveInteger('Hashtable','index1','index2','value')