Why do Julia arrays use 1-based indexing?

[lygstate]

For most language they are start with 0. Why Julia choose zero.
And from mathematical point of view, start with 0 is better.

1 1 Java 17.050% -1.43% A
2 2 C 16.523% +1.54% A
3 6 C# 8.653% +1.84% A
4 3 C++ 7.853% -0.33% A
5 8 Objective-C 7.062% +4.49% A
6 5 PHP 5.641% -1.33% A
7 7 (Visual) Basic 4.315% -0.61% A
8 4 Python 3.148% -3.89% A
9 10 Perl 2.931% +1.02% A
10 9 JavaScript 2.465% -0.09% A

[lgarron]

Depends. Mathematica uses 1-indexing, and it makes perfect sense mathematically and code-style-wise.

I haven't been able to compile / run julia, though, so I can't give a julia-specific defense. :-/

[JeffBezanson]

There is a huge discussion about this on the mailing list; please see that. If 0 is mathematically "better", then why does the field of mathematics itself start indexes at 1? We have chosen 1 to be more similar to existing math software.

[lygstate]

Can you give me the URL of the discussion?

[JeffBezanson]

http://groups.google.com/group/julia-dev/browse_thread/thread/b4d37bd859d86d84?hl=en

You might have to join the list to be able to view it.

It really isn't that interesting a topic though. We all work with both 0-based and 1-based languages and I don't think it matters that much.

[filmackay]

Sorry about bringing up a painful memory? What about sidestep the issue of 1-ness with a 'begin' just like 'end':

a[begin] = 1 # first item
a[begin+1] = 2 # second

You could leave the integral (non-begin-or-end) as is 1-based, but allow those who want to think in 0-ness to use begin in that style?

[johnmyleswhite]

I don't really see how pretending that Julia isn't 1-indexed will help people learn to use Julia, given that Julia is unambiguously 1-indexed and will stay that way. Unlike end, this way of using begin is an exact synonym for 1 in all contexts, which violates the generally desirable design guideline that there should be only standard way to do something.

[simonzack]

We have chosen 1 to be more similar to existing math software.

From a programmer's perspective, I find 1-based indexing harder to wrap around compared to python (mod operations on indexes, -1), etc.

I also thought julia's goal was to unite the mathematical and general purpose languages. In this regard, 0 based indexing is much more popular. Indexing may seem like a small thing, but you deal with it daily, more often than anything else.

[johnmyleswhite]

I don't really think this topic is open for discussion anymore.

[pao]

From a programmer's perspective, I find 1-based indexing harder to wrap around compared to python (mod operations on indexes, -1), etc.

See also mod1(), which specifically addresses this need.

[kmactavish]

Julia recommends pyplot for plotting. Pyplot uses 0-based indexing by default, so plotting plot(1:10) gives you the line y = 1:10, x = 0:9. However, since the x-axis is supposed to just be the indices when left unspecified, you would expect y = 1:10, x = 1:10 from Julia. It is troublesome that Julia would not conform to the standard set by the language that it's borrowing to fill its gaps.

[johnmyleswhite]

I'm locking this issue as there's no real possibility of this being changed.

[ihnorton]

See also: JuliaPy/PyPlot.jl#117 (comment)