Why is 20 lower than 5?

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#1

I am trying to construct a mathematical engine that can take a set of numbers written in chat by the player, and rearrange them in ascending order. To start, I am attempting to make a function which will return the lowest number in a table. Here is what I have so far;

local function Lowest(Set)
		
		for i, v in pairs(Set) do
			
			if i == 1 or Lowest > v then
				
				Lowest = v
				
			end
		end
		
		return Lowest
		
	end

For some reason, when I plug in the set “4, 20, 5”, 20 is returned as the lowest value. It seems like the code does not recognize the fact that there is a 0 at the end. I’ve tried scouring the forums, and have not stumbled upon anyone having similar issues. I am quite new to this, so I must be missing something pretty obvious!

2 Likes
#2

I think you didn’t define a variable “Lowest” in the function.

Here’s what I would write

local function GetLowestNumber(Set)
    -- set a variable "Lowest" that will hold the lowest number
    local Lowest = 0 

    -- for every thing in the set
    for _, Value in pairs(Set) do
        -- check if you need to replace the "Lowest" variable with the value in the set
        if Lowest == 0 or Value < Lowest then
            Lowest = Value
        end
    end

    return Lowest
end
1 Like
#3

Try this:

local function lowest(set)
--Assuming all entries in set are numbers
local current = nil
for i, v in ipairs(set) do
if not current then
current = v
continue 
end
current = math.min(current, v)

end
return current or error(“Empty Table”)
end
4 Likes
#4

Use a different variable name. ‘Lowest’ is already used for the function.

3 Likes
#5

This didn’t quite work, but its clever that you defined “Lowest” beforehand

1 Like
#6

That worked! I don’t quite understand what you did though?

1 Like
#7

What’s the problem? Any errors?

1 Like
#8

He basically went through each number and took the lowest number between the current number and the value at the moment.

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#9

Ah, I am still unsure as to what the problem in my original code was though.

1 Like
#10

Before urun the loop check if the indices are greater than 1, else do your algorithm checking the former to the current. The chicken or the egg solution here is to put some ridiculously high number as the first one

1 Like
#11

Well, setting current to nil first, then looping through the set. If current is nil, which will run on the first iteration since no changes were made, we set our current to the current value, then continue to the next iteration. then on the next iteration we check the lowest value between current lowest, and the current value in the set. Math.min just returns the lowest number between the two. It continues on until the last iteration.

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#12

If the table is just numbers, you can just do this:

local t = { 5, 1, 2, 7 } 
print(math.min(table.unpack(t)))
4 Likes
#13

Ah, smart! Thanks for the help!

2 Likes
#14

Not sure exactly, guess you didn’t declare Lowest other than the function that ran.

1 Like
#15

What exactly is an indice? Is that like the position in the table the number occupies?

1 Like
#16

Describes number of things in a data structure, think like #table indices is plural for index

2 Likes
#17

True, would’ve done this just forgot if math.min could take in more than 2, which i guess would make sense that it does.

1 Like
#18 
local function lowest(set)
    --Assuming all entries in set are numbers
    local current = nil
    for i, v in ipairs(set) do
        if not current then
            current = v
            continue 
        end
        current = math.min(current, v)
    end
    return current or error(“Empty Table”)
end

added indentation to make the solution more readable

3 Likes