get the key of the smallest value in a table ?

[Vrx8]

confused.. the values in the table are constantly changing.. and i want to get the key of the smallest value in the table, how do i do it ? googled it out.. find nothing

[Nixola]

Iterate over the whole table, keeping track of the lowest value.

Code: Select all

function returnMin(t)
  local k
  for i, v in pairs(t) do
    k = k or i
    if v < t[k] then k = i end
  end
  return k
end

EDIT: fixed code, as pointed by grump

[Vrx8]

Iterate over the whole table, keeping track of the lowest value.

Code: Select all

function returnMin(t)
  local k
  for i, v in pairs(t) do
    k = k or i
    if v < t[k] then k = i
  end
  return k
end

have you try it out ?

[grump]

There's an 'end' missing in Nixola's code.

Code: Select all

function returnMin(t)
  local k
  for i, v in pairs(t) do
    k = k or i
    if v < t[k] then k = i end -- end was missing here
  end
  return k
end

[Vrx8]

There's an 'end' missing in Nixola's code.

Code: Select all

function returnMin(t)
  local k
  for i, v in pairs(t) do
    k = k or i
    if v < t[k] then k = i end -- end was missing here
  end
  return k
end

still not working for me.. idk why, but I found out my own way..

[Nixola]

still not working for me.. idk why, but I found out my own way..

Could you please share how and why it did not work, and what your own way is?

[zorg]

There's an 'end' missing in Nixola's code.

Code: Select all

function returnMin(t)
  local k
  for i, v in pairs(t) do
    k = k or i
    if v < t[k] then k = i end -- end was missing here
  end
  return k
end

still not working for me.. idk why, but I found out my own way..

still not working for me.. idk why, but I found out my own way..

Could you please share how and why it did not work, and what your own way is?

Or in other words, please be as helpful as we tried to be towards you.

[Sir_Silver]

One reason it may not work for him is because it breaks if one of the values in the table is not a number. Like with this table:

Code: Select all

local table = {
	1,
	2,
	3,
	"elephant"
}

Try this instead:

Code: Select all

local function get_smallest_number(table)
	local smallest_number
	
	for k, v in pairs(table) do
		if type(v) == "number" then
			if not smallest_number then
				smallest_number = v	
			end
			
			smallest_number = v < smallest_number and v or smallest_number
		end
	end
	
	return smallest_number
end

local table = {
	1,
	2,
	"buckle_my_shoe",
	function() end,
	-69, --smallest number in the table
	{{}}
}

print(get_smallest_number(table))  --prints -69

[ivan]

Nixola's solution is the nicest, but I have a small suggestiion:

Code: Select all

function table.min(t)
  local k, v = next(t)
  for k2, v2 in pairs(t) do
    if v2 < v then
      k, v = k2, v2
    end
  end
  return k, v
end

Just make sure the table contains strictly numeric values, otherwise it doesn't make sense.
PS.A more crazy solution for numerically-indexed tables could be to use something like table.sort or math.min(unpack(t)).

[Nixola]

Table.sort and math.min solutions are not what's required, since he needs the key; it is true that my function will error in case something's not a number, and it would require several added checks.