Why do Lua arrays(tables) start at 1 instead of 0?

arrays lua lua-table
AraK picture AraK · May 7, 2010 · Viewed 56.6k times · Source

I don't understand the rationale behind the decision of this part of Lua. Why does indexing start at 1? I have read (as many others did) this great paper. It seems to me a strange corner of a language that is very pleasant to learn and program. Don't get me wrong, Lua is just great but there has to be an explanation somewhere. Most of what I found (on the web) is just saying the index starts at 1. Full stop.

It would be very interesting to read what its designers said about the subject.

Note that I am "very" beginner in Lua, I hope I am not missing something obvious about tables.

Answer

Norman Ramsey picture Norman Ramsey · May 7, 2010

Lua is descended from Sol, a language designed for petroleum engineers with no formal training in computer programming. People not trained in computing think it is damned weird to start counting at zero. By adopting 1-based array and string indexing, the Lua designers avoided confounding the expectations of their first clients and sponsors.

Although I too found them weird at the beginning, I have learned to love 0-based arrays. But I get by OK with Lua's 1-based arrays, especially by using Lua's generic for loop and the ipairs operator—I can usually avoid worrying about just how arrays are indexed.

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