Why is this loop only looping twice even though the length of array is three at the start? [closed]

Asked by

User#21908 42

6 years ago

Edited 6 years ago

I am working on debugging an algorithm I wrote and part of it has an error that is incomprehensible to me. The only way I discovered it was by printing, because it was not throwing any errors in the output. Before getting to deep into this issue I would like to mention that EgoMoose already solved my issue by recommending table.sort() and using both the first and second argument. That being said, I would still like to find out why my function was not working as intended. I don't think that this first function I will post has any relationship to the problem, but I will post it just to make sure (and satisfy the curious among you all). Note: I will likely be changing a lot of these functions because EgoMoose revealed the incredibly useful second parameter of table.sort(). I just want to find out the elusive logic error in my code so that I do not repeat it in the future. Here is the first function:

01local function findMatches(recipes, inputDictionary)
02     --[[ 
03        recipes is an array and I will reveal
04        its structure at the end of this question. 
05        inputDictionary is just a dictionary of words
06        retrieved from a lowercased string input by a user.
07    --]]
08    local newRecipeList = {unpack(recipes)}
09    --[[
10        This is so that I don't mess with the 
11        original recipes array.
12    --]]
13    local matchesList = {}
14    for i, recipe in pairs(newRecipeList) do
15        local ingredientsList = recipe.Ingredients 
16        --[[
17            Note: In Lua recipe.Ingredients
18            is the same as recipe["Ingredients"]
19        --]]
20        if ingredientsList then
21            local matchesAmount = 0
22            for i,v in pairs(ingredientsList) do
23                if inputDictionary[i:lower()] then
24                    matchesAmount = matchesAmount + 1
25                end
26            end
27            if matchesAmount > 0 then
28                recipe["Amount"] = matchesAmount
29                table.insert(matchesList, recipe)
30            end
31        end
32    end
33    return sortByLargest(matchesList) 
34    --[[
35        sortByLargest() is the function that
36        is causing me problems I just wanted
37        to provide this function so that you 
38        could see where "array" was coming 
39        from.
40    --]]
41end
 View all 41 lines...

As far as I know it is working correctly. The function that causes me the most problems is this one:

01local function sortByLargest(array) 
02    print(#array) -- this prints 3
03    local greatestArray = {}
04    while #array > 0 do
05        print("Looped")
06        local indexOfGreatestSoFar, greatestSoFar = next(array)
07        for i,v in pairs(array) do
08            print(v.Amount.." "..v.Name)
09            --[[
10                The output from these 
11                prints is as follows:
12                Looped
13                1 Beef and Cheese
14                1 Beef Cheese
15                1 Beef and flower
16                Looped
17                1 Beef Cheese
18                1 Beef and flower
19                Beef and Cheese
20                Beef Cheese
21                As you can see
22                it is only looping twice
23                when #array is 3
24            --]]
25            if v.Amount > greatestSoFar.Amount then
26                greatestSoFar = v
27                indexOfGreatestSoFar = i
28            end
29        end
30        table.insert(greatestArray, greatestSoFar)
31        array[indexOfGreatestSoFar] = nil
32    end
33    return sortByUpvotes(greatestArray)
34end
 View all 34 lines...

I hope that you can spot some kind of error or something in that function of mine. The structure of the recipes array that is passed as an argument to the recipes parameter is thus:

01local exampleListOfRecipeTypes = {
02    {
03        ["Name"] = "Beef and Cheese";
04        ["Upvotes"] = 0;
05        ["Ingredients"] = {
06            ["Salt"] = "1 tsp";
07            ["Beef"] = "1 pound";
08        };
09    };
10 
11    {
12        ["Name"] = "Beef Cheese";
13        ["Upvotes"] = 0;
14        ["Ingredients"] = {
15            ["Salt"] = "1 tsp";
16            ["Beef"] = "2 pounds";  
17        };
18    };
19 
20    {
21        ["Name"] = "Beef and flower";
22        ["Upvotes"] = 0;
23        ["Ingredients"] = {
24            ["Salt"] = "1 tsp"; 
25        };
26    };
27}
 View all 27 lines...

I would appreciate any insight on this matter. Note that an alternative solution has already been given by EgoMoose. I just want to find the elusive logic error in my code. Thanks!

The full code is over 200 lines long and that is why I did not post it all. User#21908 42 — 6y

In that case you can make the loop longer :3 greatneil80 2647 — 6y

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`1`	`array[indexOfGreatestSoFar]` `=` `array[#array]`

Why is this loop only looping twice even though the length of array is three at the start? [closed]

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