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Kotlin for data analysis

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Re: Kotlin for data analysis

#31

Post by Larrikin »

wk_end wrote: post #27
Larrikin wrote: post #22

Earlier quoted context omitted.

As someone who uses Kotlin for work and Python for side projects (and loved Python years ago in college), Python's list comprehension feature is one of the things I hate the most about the language now. As a simple example using only two collection functions I find it much easier to read val hundredOrLessEvenSeconds = (1..1000) .toList() .filter { it than hundred_or_less_even_seconds = [timedelta(seconds=it) for it i…

Not that I especially want to defend Python, but can you elaborate a bit on why you find that chain easier to read? The Python version is straightforward enough - if it's just the absence of newlines you can write hundred_or_less_even_seconds = [ timedelta(seconds=it) for it in range(1, 1001) if it Also, I don't know Kotlin well enough, but is what you wrote going to be efficient? The Python version iterates once and…

Its a small example so the efficiency doesn't matter, but you could use sequences when it does https://kotlinlang.org/docs/sequences.html .

Also the map function lets you perform any operations in it. It was a simple example but you could need to perform something slightly more complex than using another standard library function.

Re: Kotlin for data analysis

#32

Post by FridgeSeal »

wk_end wrote: post #27
Larrikin wrote: post #22

Earlier quoted context omitted.

As someone who uses Kotlin for work and Python for side projects (and loved Python years ago in college), Python's list comprehension feature is one of the things I hate the most about the language now. As a simple example using only two collection functions I find it much easier to read val hundredOrLessEvenSeconds = (1..1000) .toList() .filter { it than hundred_or_less_even_seconds = [timedelta(seconds=it) for it i…

Not that I especially want to defend Python, but can you elaborate a bit on why you find that chain easier to read? The Python version is straightforward enough - if it's just the absence of newlines you can write hundred_or_less_even_seconds = [ timedelta(seconds=it) for it in range(1, 1001) if it Also, I don't know Kotlin well enough, but is what you wrote going to be efficient? The Python version iterates once and…

What you’re doing, what you’re doing it, and any conditionals are all out of order. If you to translate the Python semantics into say, Rust syntax, you would have something akin to

.map(blah(x,y), |z|, if let (x,y) == conditional(z))

Re: Kotlin for data analysis

#33

Post by lolinder »

Blot2882 wrote: post #23
lolinder wrote: post #19

Earlier quoted context omitted.

Kotlin's standard library has ruined me for other languages, especially its collections library. The consistency and comprehensiveness of its approach to collections is unmatched in any language I've tried, including all the big name functional languages. It's hard to get across what's so great about the library in writing because it's not just one standard library function, it's how they all interact with each other…

That's interesting. I've heard complaints about Kotlins standard library in comments like this[1]. I understand they may be nitpicks but they seem annoying in practice. [1] https://www.reddit.com/r/Kotlin/comments/mh2z5u/comment/gt2n...

Hmm, coroutines are definitely a bit of a mess, but in ways that aren't super relevant when you just want to use them and not implement a framework on top of them. They definitely sacrificed implementation simplicity in favor of interface simplicity.

> don't even try to tell me that anyone uses sealed classes in practice

I use sealed classes for errors all the time.

> Nothing is concurrency safe.

Yes, but I know of no stdlib of a serious alternative that is, so I don't think that's a major concern. Don't use concurrency and you're no worse off than Python (the alternative here), and if your point of comparison is Java or similar then it's the same story there.

> All of the numbers suck. The fact that I can just call Long.toInt().toUByte() and lose a bunch of information and/or wrap a negative value into a positive value, etc, without any kind of help from the type system (maybe returning nullables) or the runtime (throwing exceptions for truncation) is gross.

Similar to the above: yes, it could be better, but it doesn't bring Kotlin's stdlib below any other major language I'm familiar with. Heck, even Rust lets you do those downcasts without a word [0], you're just supposed to know that downcasts can lose information. Lints can help you here if you care, but I don't think a language gets points docked for not having them by default—there's a balance to be struck between too few and too many explicitly-typed failure cases.

> The Map API sucks. Map::getOrElse is literally implemented incorrectly-it will call the "or else" function if the value is present in the map but is null.

That... is fair. I've never actually noticed it before, but it's wrong. The rest of the Map API has always been good for me, though.

> Dates and times suck.

In every language ever.

> I don't like how the default for the collection combinators is to be eager.

They acknowledge that they have no answer here, and neither do I. There's no pattern for Kotlin to follow because only Haskell does lazy-by-default, and Haskell isn't a model most people would want Kotlin to follow.

All in all, I read a comment like this as someone reaching for the things that irk them in a language that they actually really like—which means the items that irk them are either extremely small or actually just broken in all major programming languages.

[0] https://play.rust-lang.org/?version=stable&mode=debug&editio...

Re: Kotlin for data analysis

#34

Post by parpfish »

jillesvangurp wrote: post #12

I do both Kotlin and Python. More Kotlin than Python to be honest. But I'm pragmatic. Python is where all the action is when it comes to data science, llms, and all the rest. So it's the path of the least resistance. And there's a great argument to not challenge that and just do what everybody else does and put your head down and not criticize any of that. Which is why I use it on a few projects. The library ecosyste…

I work in a codebase that’s mostly kotlin and python and I’ve come to hate the python side.

I used to love python, but I feel like the attempts to tack on typing have really undermined it.

The “freedom” of being untyped is nice for quick little scripting things, but being typed is an absolute godsend in a real codebase.

Instead of making python pseudo-typed with messy annotations, the scientific/research community should have built out tools in an actually typed language. I think Julia hung around for years with the expectation that people were going to do that

Re: Kotlin for data analysis

#35

Post by hughesjj »

lolinder wrote: post #29
poikroequ wrote: post #24

Earlier quoted context omitted.

A bit of a contrived example, but something like this (two for statements): [x*y for x in range (10) for y in range(10)] It's not often, but occasionally there are moments where I'm writing code in Kotlin and wish I could use a list comprehension. I do prefer Kotlin overall, but there's a few things that I think would be "nice to have" from Python. Especially the yield keyword, such a wonderful way to write your own…

Hmm, I actually prefer Kotlin's version, but maybe that's just because it's what I'm used to: (0..10).flatMap { x -> (0..10).map { y -> x * y } } The flow of the data is more intuitive for me because you don't use variables before they're defined. > Especially the yield keyword, such a wonderful way to write your own iterators. Maybe I'm missing something about `yield` in Python—can it do something that Kotlin genera…

It's mostly ease of semantics -- in your example you use two layers of map and as a result need to do flatMap instead of just map twice

In py, for list/set/dictionary/generator comprehensions, the format is always the same and always the same as if you were to do it as a normal nested loop, save for the statement being first instead of last (you can also do filters using normal if statement syntax, these go at the end/after all your loops).

I actually like statement first because it gets to the "meat" of the semantics before the context (which loop etc), but end do the day it's all a bit arbitrary

@ yield, there's literally no difference between Python and kotlin. Python also offers a generator comprehension, which is nice, but it has nothing to do with yield

i_am_a_generator = ( x+1 for x in range(10*100) )

Re: Kotlin for data analysis

#36

Post by parpfish »

lolinder wrote: post #21
poikroequ wrote: post #14

Earlier quoted context omitted.

I think both languages have their strengths. I love Kotlin for its functional programming (map, filter, etc) and strong static typing. But Python has some nice features as well, such as list comprehension, the 'yield' keyword, and annotations are super simple to implement.

Are there things that you find easier to express in a list comprehension format than you do with Kotlin's standard library? I've always found comprehensions to be a bit of a workaround to the fact that Python doesn't have great support for anonymous functions, and I've never found a situation where I'm writing Kotlin really wishing I had a comprehension.

I’ve always liked that the structure of list comprehensions mirror SQL with “SELECT, FROM, WHERE” sections.

But I know that I’m in the minority that likes SQL

Re: Kotlin for data analysis

#37

Post by hughesjj »

esafak wrote: post #28
wk_end wrote: post #27

Earlier quoted context omitted.

Not that I especially want to defend Python, but can you elaborate a bit on why you find that chain easier to read? The Python version is straightforward enough - if it's just the absence of newlines you can write hundred_or_less_even_seconds = [ timedelta(seconds=it) for it in range(1, 1001) if it Also, I don't know Kotlin well enough, but is what you wrote going to be efficient? The Python version iterates once and…

It's easier to compose functions in Kotlin. The python version you showed is more ad hoc, and is really one list comprehension. I particularly like Kotlin's scope functions: https://kotlinlang.org/docs/scope-functions.html

You can do partials in python too

I do prefer python over kotlin but IMHO semantically they're both beautiful and some of the least frictive languages I've ever used

Re: Kotlin for data analysis

#38

Post by sampo »

Larrikin wrote: post #22
Blot2882 wrote: post #15

Earlier quoted context omitted.

I'm not sure how someone could see Kotlin as more expressive than Python, unless I am misinterpreting what expressive means. Python has a good language features and helpful abstractions like list comprehensions. What makes Kotlin more expressive? I understand it has some functional features but I've never seen anything dramatically flexible.

As someone who uses Kotlin for work and Python for side projects (and loved Python years ago in college), Python's list comprehension feature is one of the things I hate the most about the language now. As a simple example using only two collection functions I find it much easier to read val hundredOrLessEvenSeconds = (1..1000) .toList() .filter { it than hundred_or_less_even_seconds = [timedelta(seconds=it) for it i…

    import datetime
    import pandas as pd

    hundred_or_less_even_seconds = (
        pd.Series(range(1, 1000))
        .loc[lambda x: x

Re: Kotlin for data analysis

#39

Post by hughesjj »

Larrikin wrote: post #22
Blot2882 wrote: post #15

Earlier quoted context omitted.

I'm not sure how someone could see Kotlin as more expressive than Python, unless I am misinterpreting what expressive means. Python has a good language features and helpful abstractions like list comprehensions. What makes Kotlin more expressive? I understand it has some functional features but I've never seen anything dramatically flexible.

As someone who uses Kotlin for work and Python for side projects (and loved Python years ago in college), Python's list comprehension feature is one of the things I hate the most about the language now. As a simple example using only two collection functions I find it much easier to read val hundredOrLessEvenSeconds = (1..1000) .toList() .filter { it than hundred_or_less_even_seconds = [timedelta(seconds=it) for it i…

Gotta be real, I don't see any difference in readability (assuming it was formatted the same way, and honestly I'd prefer a different variable name than 'it' in both cases but I get that would require more boiler plate in kotlin and 'it' is a common invention).

The main difference imo is that kotlin uses more "syntax" while python uses more "English" to express the same thing. Also the half-open interval for range but that's an arbitrary decision that benefits some cases more than others (although my preference is the closed interval)

Re: Kotlin for data analysis

#40

Post by hughesjj »

jillesvangurp wrote: post #12

I do both Kotlin and Python. More Kotlin than Python to be honest. But I'm pragmatic. Python is where all the action is when it comes to data science, llms, and all the rest. So it's the path of the least resistance. And there's a great argument to not challenge that and just do what everybody else does and put your head down and not criticize any of that. Which is why I use it on a few projects. The library ecosyste…

This is exactly it for me too. Kotlin is my favorite overall language to code in, but for data analysis I'm going python for ecosystem or Julia if I need performance.
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