Table Inserting

Hello my dear friends,

I got a question on Tables:

I got a table like this

local accounts = {
[1] = {
["some"] = "thing"
},
[2] = {
["some"] = "thing"
},
[3] = {
["some"] = "thing"
},
}

so my question is: if i delete the 2nd entry in this table and this is a table where i add stuff dynamicly,
how can i detect that the 2nd index is free(any free space) to insert new data there instead of at the end of the table?

Thanks for your conclusions.

Your PrinzJuliano

If it's not a problem that the entries don't retain the same key, use table.remove and table.insert:

local accounts = {
    [1] = {
        ["some"] = "1st"
    },
    [2] = {
        ["some"] = "2nd"
    },
    [3] = {
        ["some"] = "3rd"
    },
}
table.remove(accounts, 2) -- removes the 2nd entry and decrements the key of the entries with keys larger than 2

--[[
accounts[1] remains the same
accounts[2] ceased to exist
accounts[3] moves to accounts[2]
--]]

print(accounts[2].some) -- prints "3rd"

The best part of that is no matter what happens, you'll be able to iterate through the table with a simple for loop:

for ixEntry = 1, #accounts do print(accounts[ixEntry].some) end

table.insert inserts an entry at the end of the table:

table.insert(accounts, {
    ["some"] = "2nd"
}

print(accounts[3].some) -- prints "2nd"

If you DO want to have your other values stick to their previous indexes:

-- This builds the same thing as the original table,
-- but Lua infers the line numbers for you:
local accounts = { {["some"] = "thing"}, {["some"] = "thing"}, {["some"] = "thing"} }

accounts[2] = nil  -- This removes the 2nd entry and leaves the others alone.

--[[
accounts[1] remains the same
accounts[2] ceased to exist
accounts[3] remains the same
--]]

-- "#accounts" only returns the highest index of this table before hitting a nil value.
-- "table.getn(accounts)" always returns the highest index of this table.

-- Iterating through the table (prints "thing" then "thing"):
for i=1,table.getn(accounts) do if accounts[i] then
  print(accounts[i].some)
end end

-- Inserting into the table:
accounts[#accounts+1] = {["some"] = "cabbage"}

print("")

-- Iterating through the table (this time prints "thing" then "cabbage" then "thing"):
for i=1,table.getn(accounts) do if accounts[i] then
  print(accounts[i].some)
end end