Hacker News Reader

Comment by IshKebab | Hacker News Reader

> the fact that 1-based indexing is better for scientific code (see Fortran)

It really isn't. "Scientific code" isn't some separate thing.

The only way it can help is if you're trying to write code that matches equations in a paper that uses 1-based indexing. But that very minor advantage doesn't outweigh the disadvantages by a wide margin. Lean doesn't make this silly mistake.

> If you really need the first or last element

What if you need the Nth block of M elements? The number of times I've written arr[(n-1)m+1:nm] in MATLAB... I do not know how anyone can prefer that nonsense to e.g. nm..<(n+1)m

View on HN

What if I want the nth element up to the math element? arr[n:m]. And if I want to split the array into two parts, one until the nth element and the other from the m+1st element arr[1:m] and arr[(m+1):end]. Julia matches how people speak about arrays, including C programmers in their comments. Arrays are (conceptually) not pointer arithmetic. Also for your usecase typically you would just use a 2d array and write a[n,:].

> arr[n:m]

arr[n..=m]

> arr[1:m] and arr[(m+1):end]

arr[0..m], arr[m..]

Much nicer.

> Arrays are (conceptually) not pointer arithmetic.

Look at a ruler. Does it start at 1?

This is such a classic example of online discourse in general. There are two options, and folks tribally cling to one or the other without realizing that both are legitimate and well-suited for different situations.

Yes, of course distances are measured starting from 0. But we count discrete things starting at 1. You can do mental gymnastics to enumerate from zero and many programmers are (unfortunately IMO) taught to do so. It's a hard thing to learn that way, so for the folks that have done so, it often becomes a point of pride and a shibboleth.

As a classic example, a four story building has four floors. But you only need to go up three flights to get to the top. You can legitimately call the top floor either 3 or 4, and folks are similarly tribal about their own cultural norms around this one, too.

> There are two options, and folks tribally cling to one or the other without realizing that both are legitimate and well-suited for different situations.

No I disagree entirely. One is simply better.

> It's a hard thing to learn that way, so for the folks that have done so, it often becomes a point of pride and a shibboleth.

It is not hard. It's not better because it's hard-won knowledge. It's better because it leads to simpler, more elegant code. Simple as.

Thanks for proving my point perfectly.

Fully agreed. I first struggled when switching from python to Julia, then ended up finding it slightly better for my use cases (which includes teaching scientists who are not programmers). But it's simply not a big deal either way. I am also reminded of the significant whitespace objections to python in the old days, before python took over everything...

> arr[n..=m]

so you just need to overload the syntax of intervals even more to make it work

> arr[0..m], arr[m..]

now `m` refers to different things depending on which side of the interval it's on. less characters doesn't mean nicer

I get it though, I was skeptical about 1-based indexing when I started Julia. By the nature of indices vs length there will always be an off-by-one problem: either you have elements [n, m - 1] with length (m - n) or [n, m] with length (m - n + 1). Unless you're doing a bunch of pointer arithmetic type stuff, I find the symmetry of a inclusive-inclusive interval to be a better default.

As a final rebuttal I offer: range(n - 1, -1, -1)

Your second point is the main argument for me personally. Numbers in brackets always mean the same thing: the ordinal number of the references object in an ordered collection. In 0 based indexing you can think of the number as refering to the space between the referenced objects. But that is simply an additional mental image on top of the original one.

As a neat bonus, in Julia 1:5 is just the iterator for the numbers 1 to 5. So slicing is typically not some special syntax either. It all works rather nicely.

So if I have a row of 5 apples, I can say "take the second and third apple" or I can say "take the apples between one apple length and three apple lengths from the start".

Which is more natural? The ruler is exactly the right mental image if an array to you is a partitioned region of memory starting at a specific pointer location. If an array to you is an ordered collection of objects, you would never invent 0-based indexing or inclusive-exclusive slicing.

Either way, it's not a big deal. I have lived in both worlds, I have come to think Julia is a bit more natural and easier to teach. But it ls really the silliest bike shedding complaint, given that the language has considerable real trade offs.

>It really isn't.

They way people reveal themselves is a pattern worthy of taking note.

Reply on news.ycombinator.com