Lua: Tip - Safely remove items from an array table while iterating

[spk77]

I was searching for the best way to remove values from an array-like table and I found this function:https://stackoverflow.com/questions/...hile-iterating.

table.remove is slow:

• table.remove causes all of the subsequent (following) array indices to be re-indexed every time you call it to remove an array entry.

This function removes values and compacts/re-indexes the table within a single loop:

------------------------------------------------------------
function table_remove(t)
  local new_index = 1
  local n = #t
  for old_index = 1, n do
    local value = t[old_index]
    -- (This is a random example - remove every other value from the table)
    if value%2 == 0 then -- KEEP if true...
      -- Move old_index's kept value to new_index's position, if it's not already there.
      if old_index ~= new_index then
        t[new_index] = t[old_index]
        t[old_index] = nil
      end
      new_index = new_index + 1 -- Increment position of where we'll place the next kept value.
    else -- ... else REMOVE
      t[old_index] = nil
    end
  end
  return t
end

-- Example:
local t = {1,2,3,4,5,6,7,8,9,10}

reaper.ClearConsole()

for i=1, #t do
  reaper.ShowConsoleMsg(tostring(t[i]) .. " ")
end
reaper.ShowConsoleMsg("\nOriginal table length = " .. tostring(#t) .. "\n")

t = table_remove(t)

reaper.ShowConsoleMsg("\n")
for i=1, #t do
  reaper.ShowConsoleMsg(tostring(t[i]) .. " ")
end
reaper.ShowConsoleMsg("\nTable length after removing values = " .. tostring(#t))

[deeb]

Maybe create just a new table with the valid values and then set this table as the original one ! Is it that slow?