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math.random with Tables Dictionary?

Asked by

7 years ago

local Types = { ["LeftPunch"] = {Id = 1784490345, DamagePart = "LeftHand", Damage = 10}, ["RightPunch"] = {Id = 1784483797, DamagePart = "RightHand", Damage = 10} }

local Type = Types[math.random(1, #table)] print(Type)

it keep saying interval is empty

#Types instead of #table? User#20279 0 — 7y

nope MaxOutGaming -3 — 7y

You don't have a table named "table" and you can't anyways. MooMooThalahlah 421 — 7y

3 answers

Answered by

MooMooThalahlah 421

7 years ago

Edited 7 years ago

I did some reading up on why you can't print(Types[1]). Or print(#Types) keeps returning 0. Here's a quote from:

lua.users.org

The # operator doesn't count all the items in the table (!). Instead it finds the last integer (non-fractional number) key. Because of how it's implemented its results are undefined if all the integer keys in the table aren't consecutive. Which is why it shouldn't be used for tables used as sparse arrays[2]).

If you go to the website and click the "2" it will lead you to Wikipedia and you can read more about it.

Interval is empty because you tried to do math.random(1,0)

Not sure if this is the best approach but you can explicitly assign an Index value in your tables.

01-- Assign your own index
02local Types = {
03    ["LeftPunch"] = {Index = 1, Id = 1784490345, DamagePart = "LeftHand", Damage = 10},
04    ["RightPunch"] = {Index = 2, Id = 1784483797, DamagePart = "RightHand", Damage = 10}
05}
06local numOfPunches = 0
07 
08print("What is #table: " .. #table)
09--print(math.random(1,0)) -- Interval is empty
10--print(math.random(1,#table)) -- Interval is empty
11 
12print(#Types) -- Prints 0
13-- Not what we wanted
14print(Types[1]) -- Prints nil
15-- Also not what we wanted
16 
17-- Counts how many entrys you have in your matrix
18-- Useful if you plan to add or remove punches
19for punchType,entry in pairs(Types) do
20    numOfPunches = numOfPunches + 1
21    print(punchType .. " " .. tostring(entry))
22end
23print("You have " .. numOfPunches .. " types of punches.\n")
24 
25local function RandomPunch()
26    local rng = math.random(1,numOfPunches)
27 
28    for _,entry in pairs(Types) do
29        -- Compare it to the Index assigned at the top
30        if entry.Index == rng then
31            print(entry.DamagePart .. " did " .. entry.Damage .. " damage.")
32        end
33    end
34end
35 
36while wait(1) do
37    RandomPunch()
38end
 View all 38 lines...

Answered by

hellmatic 1523

7 years ago

Edited 7 years ago

01local Types = {
02    Enabled = true
03 
04    ,RightPunch = {
05        Enabled = true
06 
07        ,Damage = 10
08 
09        ,Id = 1784483797
10        ,Hand = "RightHand"
11     }
12 
13    ,LeftPunch = {
14        Enabled = true
15 
16        ,Damage = 10
17 
18        ,Id = 1784490345
19        ,Hand = "LeftHand"
20     }
21 
22}
23 
24local RightPunch = Types.RightPunch
25local LeftPunch = Types.LeftPunch
26 
27local randomtype = nil
28 
29function RANDOM()
30    randomtype = math.random(1, 2) -- 1 = Right, 2 = Left
31 
32    if (randomtype == 1) then
33        print("Chose " .. RightPunch.Hand .. ". Damage:" .. RightPunch.Damage "")
34 
35    elseif (randomtype == 2) then
36        print("Chose " .. LeftPunch.Hand .. ". Damage:" .. LeftPunch.Damage "")
37    end
38end
39 
40function PUNCH()
41    RANDOM()
42end
 View all 42 lines...

Answered by

Validark 1580

7 years ago

Here is a generalized WeightedProbability Generator function. It is also installable through the RoStrap plugin. Documentation available here.

01local WeightedProbabilities = {}
02 
03local WeightedProbabilityFunction =  {
04    -- Generates option-picker functions from relative probabilities
05    -- @readme https://github.com/RoStrap/WeightedProbabilityFunction/blob/master/README.md
06    -- @rostrap WeightedProbabilityFunction
07    -- @author Validark
08 
09    new = function(ProbabilityData)
10        -- @param dictionary in the form: {
11        --      [variant option1] = number Weight1;
12        --      [variant option2] = number Weight2;
13        -- }
14        -- @returns a function that, when called, selects an option from its probability and returns it
15 
16        local n = 0
17        local TotalWeight = 0
18        local Options = {}
19        local RelativeWeights = {}
20 
21        for Option, RelativeWeight in pairs(ProbabilityData) do
22            assert(type(RelativeWeight) == "number", "ProbabilityData must be in the form {variant Option = number Weight}")
23            assert(RelativeWeight >= 0, "Weights must be non-negative numbers")
24 
25            n = n + 1
26            TotalWeight = TotalWeight + RelativeWeight
27 
28            Options[n] = Option
29            RelativeWeights[n] = RelativeWeight
30        end
31 
32        ProbabilityData = nil
33 
34        assert(TotalWeight ~= 0, "Please give an option with a weight greater than 0")
35 
36        for i = 1, n do
37            RelativeWeights[i] = RelativeWeights[i] / TotalWeight
38        end
39 
40        local function Pick(Picked)
41            Picked = Picked or math.random()
42 
43            for i = 1, n do
44                Picked = Picked - RelativeWeights[i]
45                if Picked < 0 then
46                    local Option = Options[i]
47                    return WeightedProbabilities[Option] and Option() or Option
48                end
49            end
50        end
51 
52        WeightedProbabilities[Pick] = true
53 
54        return Pick
55    end
56}
57 
58local Types = {
59    LeftPunch = {
60        Id = 1784490345;
61        DamagePart = "LeftHand";
62        Damage = 10;
63    };
64 
65    RightPunch = {
66        Id = 1784483797;
67        DamagePart = "RightHand";
68        Damage = 10;
69    };
70}
71 
72local RandomPunch = WeightedProbabilityFunction.new {
73    [Types.LeftPunch] = 0.5;
74    [Types.RightPunch] = 0.5;
75}
76 
77table.foreach(RandomPunch(), print)
 View all 77 lines...

math.random with Tables Dictionary?

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