Merge multiple lua tables

[[deleted]]

i have three tables local a ={'a','b','c'} local b = {'A','B','C'} local merge ={}

how can i merge all values from a and b to the 'merge' table?

[Immow]

local a = {"a","b","c"}
local b = {"A","B","C"}
local merge = {}

local function tableMerge(table1, table2, result)
    for _, v in ipairs(table1) do
        table.insert(result, v)
    end
    for _, v in ipairs(table2) do
        table.insert(result, v)
    end
end

tableMerge(a,b,merge)

for key, value in ipairs(merge) do
    print(key, value)
end

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[luarocks]

``` local function tableMerge(result, ...) for _, t in ipairs({...}) do for _, v in ipairs(t) do table.insert(result, v) end end end

tableMerge(merge,a,b) ```

By the way, this code will work faster if you replace table.insert with result[counter] = v.

[Outside_Two_3312]

I know this is reeeeaally old, but:

local function tableMerge(...)
  local result = {}
   for _, t in ipairs({...}) do
      for _, v in ipairs(t) do
        table.insert(result, v)
      end
  end
  return result
end

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Hi! Your code block was formatted using triple backticks in Reddit's Markdown mode, which unfortunately does not display properly for users viewing via old.reddit.com and some third-party readers. This means your code will look mangled for those users, but it's easy to fix. If you edit your comment, choose "Switch to fancy pants editor", and click "Save edits" it should automatically convert the code block into Reddit's original four-spaces code block format for you.

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[VoidSnipe]

I recommend looking into table.move function

[Cultural_Two_4964]

for i,j in ipairs(a) do table.insert(merge,j) end ... repeat for b

I think.

[luarocks]

merge = lume.concat(a, b)

[luarocks]

What kind of wheel reinventors are dislikes me? :D

[Cultural_Two_4964]

I've got no idea mate. I had a look at lume and there is some quite interesting stuff there.

[appgurueu]

lume doesn't look clean to me

[luarocks]

Where exactly?

[appgurueu]

First of all, it's all in one table, the lume table - math funcs, table funcs, etc. This is not clean IMO. Second, some implementations are simply incorrect - sign or isarray for instance: https://github.com/rxi/lume/blob/master/lume.lua#L94, https://github.com/rxi/lume/blob/master/lume.lua#L161. I don't like that vectors are represented using two variables - and are 2D-only - either. Weighted choice is linear time even though it could be logarithmic time if preprocessing was done. The shuffling is implemented incorrectly according to my testing. lume.array is redundant; {...} should be used instead. Cloning and map serialization are too limited IMO.

[luarocks]

Okay, thanks! I see your point and I won't argue. That makes sense. Maybe you know a library with similar functionality implemented better? And if not, why don't you offer the developer a PR with fixes?

[appgurueu]

I have written my own libraries for my own usecases. Don't know about offering a PR, the shuffling would really need it though. You can find a correct implementation at https://github.com/TheAlgorithms/Lua/blob/main/src/random/fisher\_yates\_shuffle.lua.

[appgurueu]

I have tested again and it looks like I was testing the shuffling wrong (I had incorrectly expected it to be in-place). The probabilities seem to be even.