Lua arrays start at 1. One major reason for this is the convention.
Lua arrays start at 1 That said, i really dont care, in Lua its 1 and in others its 0. The precedent is nearly set in stone already, so we should continue to add pressure to force new languages to start arrays as 0 as well. The only real point that still holds water against 1-based indexing is that it breaks modulo arithmetic and related operations for iterating over arrays, but in a language with iterators and functional iterator operations like reversing and chaining, even that doesn't really matter. This makes comparisons and slicing much more intuitive. Unfortunately forking Lua to change it to 0-based would also break backwards compatibility. ) [Like everywhere in Lua, arrays start at 1. One major reason for this is the convention. It made sense back in the old days to start with zero, because then you can have 256 elements in an array instead of 255. Every index is separated by a comma and the first index is 1, so “array value 1” has index 1, workspace. e. If history had gone differently and the majority of languages today started arrays at 1 instead of 0, then I'd be advocating for starting arrays at 1 instead. cat[1] = animal. If you have no good reason to start at 0, make it start at 1. In Lua, array indexes start at 1, not 0. 2: Why One? Some languages such as Lua Jan 6, 2021 · I have been trying to use multidimensional arrays and I am unsure on how I would declare it at the start in this situation In C#, I would have just declared it like this: float[,,] array1 array1 = new float[30, 20 ,30] In Lua, I have tried to replicate this but i believe i am not actually creating a multidimensional array but just a single one Apr 26, 2023 · local array_value_2 = "hello world" local my_table = {"array value 1", array_value_2, workspace. Although, as stated by the lua. As pointer math is non-existent in languages higher-level than C, the memory offset argument breaks down. its more than that. So you're going to need to make your own custom constructor which means additional overhead. fish -- and likewise if you want index 0: animal. The size of an array is not fixed and it can grow based on our requirements, subject to memory Tables can be used as arrays, dictionaries, or a mix of both; Array indices in Lua start at 1, not 0; We can access table elements using square brackets or dot notation; The ipairs() function is used to iterate over array-like tables; Lua Standard Libraries. By default, arrays designate the first item in an array as index 1. We will however go into more things than only tables. Jul 19, 2021 · Why do Lua arrays (tables) start at 1 instead of 0? Yes, the arrays in Lua start with index 1 as the first index and not index 0 as you might have seen in most of the programming languages. Remember that most functions assume that arrays start at index 1, and therefore will not handle such arrays correctly. But it makes sense! First element have index 1, second have 2, etc. In Lua, you can access array elements using the square bracket notation []. cat[1] to have the same value (the same lua table) just do a regular assignment: animal. Also, all built-in functions that expects 1-based arrays will completely break:. length(arr) always gives the last element index (and inside an array index, shorthand is $). The Lua libraries adhere to this convention; so, if your arrays also start with 1, you will be able to use their functions directly. Code like this would be completely valid local t = { } for i = 0, 2, 1 do t[i] = i end. But it's no problem if your arrays start at 0 – that extra slot is simply stored in the hash, together with the key. It is standard coding practice and most programmers are used to thinking of arrays in that manner. fish and animal. And you would have your "array" t start at 0. The convention for indexing across Lua libraries is to begin with 1 in lieu of 0. Net there was VB classic (VB6) it has a directive to define the base index of array, if the directive is omitted by default array index starts from zero, it is defined by typing Option Base 1 at the beginning of the code blocks. This tutorial will cover (in order): The static array Implementing a dynamic array Implementing hash tables with only numbers Implementing hash tables with all types Aug 23, 2017 · Before VB. Some of Lua's API calls use tables, and begin counting at 1. . Consider the example shown below −. arrays in that language start at index 0. You can start an array at index 0, 1, or any other value: -- creates an array with indices from -5 to 5 a = {} for i=-5, 5 do a[i] = 0 end However, it is customary in Lua to start arrays with index 1. 1 Internals: Tables I I will try to explain how tables work internally within Lua 5. It's far less of a learning curve, and better in some cases. These trailing commas are optional, but are always valid: That is why the argument is asymmetrical. Lua的设计者之一Rafal Ipanema在设计语言时，受到Pascal 1-indexing is common among languages targeting scientific computing (plus Lua), because that's how we index vectors and matrices in math. Since you can index a table with any value, you can start the indices of an array with any number that pleases you. Indexes are assigned to values in the order in which the values are stored. Oct 11, 2014 · I'm porting FFT code from Java to Lua, and I'm starting to worry a bit about the fact that in Lua the array part of a table starts indexing at 1 while in Java array indexing starts at 0. Part, function()end, {}} The array has a hidden element which is the index. Use array indexes. For the input array this causes no problem because the Java code is set up to handle the possibility that the data under consideration is not located at the The part that makes it funny is that it is generally a stupid idea to force an array to start at 1. However, arrays can be created to use any custom set of indices prescribed. You can always put a comma after the last entry. Unfortunately the feature that I refer to is Lua's open source license. In Euphoria, for example, sequences (the parallel to arrays) start at 1. let &arr be “address” case 1 ( array indices start from 1 ) : Apr 13, 2017 · (Then the position in that array is the key. Sep 1, 2023 · In Lua, arrays can be created with curly braces {}. I was unable to find a patch or fork of Lua that changed the 1-based nature of the language. Each value in the array is assigned an index number. In the array just created, "Hi" is at index 1, and "Goodbye!" is at index 3. In Lua, arrays are implemented using indexing tables with integers. Language Examples ----- 1- lua In Lua, tables (akin to arrays) begin at index 1. Sep 28, 2020 · local x={1,2,3} x[0] = 5 -- is the x[0] a key or index? This is not right! There are no arrays in lua. cat. If you set up your arrays to start at 1, then it could imply several things: Feb 6, 2025 · 而在以0为起始索引的语言中，访问第n个元素需要使用array[n-1]。 历史原因. We will, in this tutorial, write our own basic implementation of Lua’s tables. May 28, 2024 · Let us assume a 2D array and write a row-major formula with two different approaches: array indices starting from 1; array indices starting from 0; let the 2D array be arr[m][n] of type int. Lua doesn't have arrays, it only has tables, and both 0 and 1 are just keys, and having a 0 key is totally a thing you can do. 1. Jan 19, 2021 · The thing that people who don't really know Lua don't get is that Lua doesn't give a shit whether you start at 1 or at 0. cat[0] = animal. Live Demo. Accessing Elements In An Array. Lua comes with several built-in libraries that provide useful functions. However, it is customary in Lua to start arrays with 1 (and not with 0, as in C) and several facilities stick to this convention. Part has index 3. Every (99%) other language has a zero based array or list. Oct 31, 2013 · If you want animal. This is what makes the array and dictionary As shown by your example, arrays constructed the native way will start at 1. Some coding languages, like Java, start indexes at 0. Lua doesn't have arrays. Also, the reference implementation of Lua optimizes integer indexes starting with 1 in a faster data structure. When the directive is defined arrays index starts from one Dec 27, 2019 · The majority of programming languages use 0-based indexing i. This design aligns with Lua's user-friendly philosophy. This code, for example, will allow us to access the second element of the arr array: Hmmm. Aug 7, 2010 · I think that that Lua already has the feature that you need to make it 0-based. Basically it becomes a question of "The normal way for programmers vs the normal way for mathematicians". Every language I can think of (except Lua) has arrays that start at 0. 1. Lua has hashmaps (called tables) that can take any Lua data type as a key. Its rare i index into arrays anyway, as i find it very brittle. Square brackets enclose the index of the element you want to access. But if you'd have to adjust an algorithm or formula to do that, just start Sep 1, 2019 · Lua 5. It's a testament to the diversity of programming paradigms and their adaptation to different needs. org page, "arrays" in lua are allowed to start at any index they want, but guess why, it's because they are not arrays, they are tables Nov 25, 2023 · The choice of 1-based indexing affects everything from algorithm design to beginner learning curves. The first value is at index 1, the second at index 2, and so forth. fish Note that many of the standard lua functions that work with tables start counting from 1.
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