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I love Julia in general, but yeah, I hate `end`. Re: 0-indexing vs 1-indexing. If you use 0-indexing, you turn off a lot of non-engineering scientific program

I love Julia in general, but yeah, I hate `end`. Re: 0-indexing vs 1-indexing. If you use 0-indexing, you turn off a lot of non-engineering scientific programmers. My personal experience is that 0-indexing is better for more engineering applications, while 1-indexing is better for math. I'm a weirdo in that I don't seem to mind either one though.

skohan 6y ago
Is there an example of where 1 is better for math, or is it just a familiarity thing?
- SatvikBeri 6y ago
  As a trivial example, if you want to get the sum of the first n numbers, that's `sum(range(n+1))` in Python. Or if you want to get all the prime numbers <= n, find the triangular numbers, etc. In general you end up with a lot of `n+1`s and it's easy to lose track or miss some, and end up with a silent, non-crashing error that produces the wrong result because you're accidentally leaving out the last element of your input.
- socialdemocrat 6y ago
  Most math books are written in a way where 1 is the first element. So if you take math examples and translate to code, it works more naturally. Also this is how you talk normally. You don't talk about the zeroth-column or zeroth-row in daily speech. You talk about first column and first row. Only reason 0 based indexing make sense to me is because I began programming as a teenagers and was forced to get accustomed to it. But I remember struggling with it. Yes when working with memory, pointers etc it is more elegant. But if you are not, then I think 1-based indexing looks better.
- FridgeSeal 6y ago
  Zero based indexing came from early requirements to address things in arrays using offsets. Subsequent languages don’t have this issue, and when you think about it, it causes a weird disconnect: 1-based indexing corresponds exactly with how you think about and see elements in a collection. 0 based indexing-despite how comfortable one gets with it requires additional arithmetic. It’s a relic from the past, and unless you’re doing the very specific thing of indexing via offset instead of position, there’s no reason to hang onto this anachronism.
- cbkeller 6y ago
  Linear algebra is the most practically consequential one - and suffice it to say, it’s not a coincidence that BLAS, LINPACK, and LAPACK were all written in one-based languages. Matrix indexing is one-based, and beyond the issue of translating notation from equations, IIRC there is even a slight performance difference in some cases. I believe what it really comes down to is that, just as zero-based really is more natural for offsets (zero offset means the first position, great for pointers), one based really is more natural for counting [and _sets_] (when your index is n that means you have counted n elements up until now).
cambalache 6y ago
> you turn off a lot of non-engineering scientific programmers. I think you mean "non-CS engineers". CS is a minuscule branch of engineering. Plenty of chemical, mechanical, civil (and so on) engineers had their whole education doing maths and programming with 1-indexing. > I'm a weirdo in that I don't seem to mind either one though. You are not, as an outsider this is one of the less appealing parts of practical CS, endless bickering about non-substantive issues which most of the time boil down to a matter of personal preference (see also tabs vs spaces, vim vs emacs, react vs vue, golang vs rust and on and on and on...)
mjcohen 6y ago
I don't understand why Julia didn't do like Fortran and Ada and allow any starting index. E.g., a(-5:5, 0:3).
- SatvikBeri 6y ago
  I mean, Julia is flexible enough that it's pretty easy to implement arrays with different indexing schemes that have the same performance as built-in arrays: https://github.com/JuliaArrays/OffsetArrays.jl https://github.com/JuliaArrays/OffsetArrays.jl
- kirill5pol 6y ago
  In case you didn’t know, Julia does in fact have arbitrary indexing! https://docs.julialang.org/en/v1/devdocs/offset-arrays/ https://docs.julialang.org/en/v1/devdocs/offset-arrays/

skohan 6y ago

Is there an example of where 1 is better for math, or is it just a familiarity thing?

SatvikBeri 6y ago
As a trivial example, if you want to get the sum of the first n numbers, that's `sum(range(n+1))` in Python. Or if you want to get all the prime numbers <= n, find the triangular numbers, etc. In general you end up with a lot of `n+1`s and it's easy to lose track or miss some, and end up with a silent, non-crashing error that produces the wrong result because you're accidentally leaving out the last element of your input.
socialdemocrat 6y ago
Most math books are written in a way where 1 is the first element. So if you take math examples and translate to code, it works more naturally. Also this is how you talk normally. You don't talk about the zeroth-column or zeroth-row in daily speech. You talk about first column and first row. Only reason 0 based indexing make sense to me is because I began programming as a teenagers and was forced to get accustomed to it. But I remember struggling with it. Yes when working with memory, pointers etc it is more elegant. But if you are not, then I think 1-based indexing looks better.
FridgeSeal 6y ago
Zero based indexing came from early requirements to address things in arrays using offsets. Subsequent languages don’t have this issue, and when you think about it, it causes a weird disconnect: 1-based indexing corresponds exactly with how you think about and see elements in a collection. 0 based indexing-despite how comfortable one gets with it requires additional arithmetic. It’s a relic from the past, and unless you’re doing the very specific thing of indexing via offset instead of position, there’s no reason to hang onto this anachronism.
cbkeller 6y ago
Linear algebra is the most practically consequential one - and suffice it to say, it’s not a coincidence that BLAS, LINPACK, and LAPACK were all written in one-based languages. Matrix indexing is one-based, and beyond the issue of translating notation from equations, IIRC there is even a slight performance difference in some cases. I believe what it really comes down to is that, just as zero-based really is more natural for offsets (zero offset means the first position, great for pointers), one based really is more natural for counting [and _sets_] (when your index is n that means you have counted n elements up until now).

cambalache 6y ago

> you turn off a lot of non-engineering scientific programmers. I think you mean "non-CS engineers". CS is a minuscule branch of engineering. Plenty of chemical, mechanical, civil (and so on) engineers had their whole education doing maths and programming with 1-indexing. > I'm a weirdo in that I don't seem to mind either one though. You are not, as an outsider this is one of the less appealing parts of practical CS, endless bickering about non-substantive issues which most of the time boil down to a matter of personal preference (see also tabs vs spaces, vim vs emacs, react vs vue, golang vs rust and on and on and on...)

mjcohen 6y ago

I don't understand why Julia didn't do like Fortran and Ada and allow any starting index. E.g., a(-5:5, 0:3).

SatvikBeri 6y ago
I mean, Julia is flexible enough that it's pretty easy to implement arrays with different indexing schemes that have the same performance as built-in arrays: https://github.com/JuliaArrays/OffsetArrays.jl https://github.com/JuliaArrays/OffsetArrays.jl
kirill5pol 6y ago
In case you didn’t know, Julia does in fact have arbitrary indexing! https://docs.julialang.org/en/v1/devdocs/offset-arrays/ https://docs.julialang.org/en/v1/devdocs/offset-arrays/