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    <p>Yes it is 4.</p> <p>From the Lua reference manual:</p> <blockquote> <p>The length of a table t is defined to be any integer index n such that t[n] is not nil and t[n+1] is nil; moreover, if t[1] is nil, n can be zero. For a regular array, with non-nil values from 1 to a given n, its length is exactly that n, the index of its last value. If the array has "holes" (that is, nil values between other non-nil values), then #t can be any of the indices that directly precedes a nil value (that is, it may consider any such nil value as the end of the array).</p> </blockquote> <p>Let's modify the code to see what is in the table:</p> <pre><code>local objects = {} local foo = #bar * 3 for i=1, foo do objects[i] = bar[quantizeNumber(i, 3)] print("At " .. i .. " the value is " .. (objects[i] and objects[i] or "nil")) end print(objects) print(#objects) </code></pre> <p>When you run this you see that <code>objects[4]</code> is 3 but <code>objects[5]</code> is <code>nil</code>. Here is the output:</p> <pre><code>$ lua quantize.lua At 1 the value is nil At 2 the value is 3 At 3 the value is 3 At 4 the value is 3 At 5 the value is nil At 6 the value is nil At 7 the value is nil At 8 the value is nil At 9 the value is nil At 10 the value is nil At 11 the value is nil At 12 the value is nil At 13 the value is nil At 14 the value is nil At 15 the value is nil table: 0x1001065f0 4 </code></pre> <p>It is true that you filled in 15 slots of the table. However the <code>#</code> operator on tables, as defined by the reference manual, does not care about this. It simply looks for an index where the value is not nil, and whose following index <strong>is</strong> nil.</p> <p>In this case, the index that satisfies this condition is 4.</p> <p>That is why the answer is 4. It's just the way Lua is.</p> <p>The nil can be seen as representing the end of an array. It's kind of like in C how a zero byte in the middle of a character array is actually <em>the end of a string</em> and the "string" is only those characters before it.</p> <p>If your intent was to produce the table <code>1,1,1,2,2,2,3,3,3,4,4,4,5,5,5</code> then you will need to rewrite your <code>quantize</code> function as follows:</p> <pre><code>function quantizeNumber(i, step) return math.ceil(i / step) end </code></pre>
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    1. POStrange table error in Lua
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    1. USRay Toal
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    1. COBut `bar` is five elements long. I should be doing a for loop from 1 to 15, 15 being the length of bar * 3, as I specified earlier. Shouldn't that leave me with 15 items? Why am I getting 4 items?
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    2. CO@Elliot, I've answered this question in an edit to my answer. HTH.
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    3. COOkay, so I'm filling my array up to item 4. Why isn't it going past index 4? I'd expect that the output would like something like this: 1, 1, 1, 2, 2, 2, 3, 3, 3, ... 5, 5, 5. Why isn't it? What am I doing wrong?
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