4 ms·

> Everything in JavaScript is an object, even Arrays. So even an Array lookup is O(1) in JavaScript - not true in Python where it has to search the Array. Huh?

> Everything in JavaScript is an object, even Arrays. So even an Array lookup is O(1) in JavaScript - not true in Python where it has to search the Array. Huh? Array and list lookups are O(1) in Python too. Who told you that? Searching is different, and it's O(n) in both JS and Python. Can you really believe two mainstream programming languages can have such a drastic difference in time complexity? Also, not my comment, but: > JS uses some heuristics to decide whether to use a hashmap or to make the object as a static struct" neither hashmap nor struct exists in JS, just funny. I'm pretty sure they meant that Javascript internally uses either a hashmap or a struct (you can do something close in Python using __slots__) to represent an object. Those are standard data structure names, even though Javascript doesn't use the same terminology. Python doesn't call them hashmaps either.

_akhe 3y ago
My bad it's on the insertion side, you can O(1) insert into the middle of Array-likes like Set in JS (which I use in this lib), where I think Python is O(n) for all it's Array-likes. Think you can O(1) append to an Array though. But there are at least a few other reasons Python is generally slower than JavaScript. It's popular in ML because it was popular in math, and it was popular in math because it's easy to teach in schools. People use Python for its ML libraries, and now its ML communities, not because it's a fast language - it isn't really. And has no browser implementation, so there are a few reasons I didn't choose Python. Reading it again I think I understand what the other poster meant now, but they also said "multi-process has nothing to do with the language" when it does have a lot to do with scaling Node especially to handle concurrency. I did a little demo here a while ago to show what I mean, check out the browser tab example: https://github.com/bennyschmidt/simple-node-multiprocess https://github.com/bennyschmidt/simple-node-multiprocess Thanks for your comments, I hate language vs language debates! :D
- selcuka 3y ago
  > you can O(1) insert into the middle of Array-likes like Set in JS Sets are supposed to retain the insertion order. I don't think you can insert into the middle, let alone in O(1) time (as they are hashmaps, not linked lists). > I hate language vs language debates! I wasn't trying to compare JS to Python. My aim was to clarify a misunderstanding re: data structures used.
  - _akhe 3y ago
    In the case of `Set` and `Map` they're keys though. It's sorted in that you can reference `data[1]` and get that element, but I don't know the keys are necessarily sorted. This guy says "V8 team explains how some memory optimization was done on its hashtable implementation for Map, Set, WeakSet, and WeakMap: Optimizing hash tables: hiding the hash code Based on 1 and 2: V8's Set and Map's get & set & add & has time complexity practically is O(1)." https://stackoverflow.com/questions/33611509/es6-map-and-set-complexity-v8-implementation https://stackoverflow.com/questions/33611509/es6-map-and-set...
mpeg 3y ago
I wouldn't bother arguing with this guy, he deliberately misquoted me on every point to make it seem like what he's saying is correct Indeed I was talking about the internals of v8, and even linked a blog post explaining it, v8 is written in c++ so it doesn't use javascript data structures anyway.
- _akhe 3y ago
  Haha dude you think Python is fast, and said multi-process has nothing to do with JavaScript, so of course I'm going to write off anything you think at this point because you know nothing about dynamic languages. I missed the V8 bit because I was replying to a lot of people - your overall point is still terrible because JavaScript is a lot faster than Python. Think about the larger point you're making. Btw sometimes you say "it's just an OS feature" when convenient but you don't say "it's just an interpreter feature" (regarding V8) - I wonder at what point in the debate that will come out. That's why I hate these kinds of debates, they're all signaling and changing subjects and losing sight of the point being made. Whenever I'm talking about time complexity, I'm in a terrible conversation that I can't wait to get out of. The bottom line is everybody in the world except you knows Python is slow as hell, and for more than 1 reason.

_akhe 3y ago

My bad it's on the insertion side, you can O(1) insert into the middle of Array-likes like Set in JS (which I use in this lib), where I think Python is O(n) for all it's Array-likes. Think you can O(1) append to an Array though. But there are at least a few other reasons Python is generally slower than JavaScript. It's popular in ML because it was popular in math, and it was popular in math because it's easy to teach in schools. People use Python for its ML libraries, and now its ML communities, not because it's a fast language - it isn't really. And has no browser implementation, so there are a few reasons I didn't choose Python. Reading it again I think I understand what the other poster meant now, but they also said "multi-process has nothing to do with the language" when it does have a lot to do with scaling Node especially to handle concurrency. I did a little demo here a while ago to show what I mean, check out the browser tab example: https://github.com/bennyschmidt/simple-node-multiprocess https://github.com/bennyschmidt/simple-node-multiprocess Thanks for your comments, I hate language vs language debates! :D

selcuka 3y ago
> you can O(1) insert into the middle of Array-likes like Set in JS Sets are supposed to retain the insertion order. I don't think you can insert into the middle, let alone in O(1) time (as they are hashmaps, not linked lists). > I hate language vs language debates! I wasn't trying to compare JS to Python. My aim was to clarify a misunderstanding re: data structures used.
- _akhe 3y ago
  In the case of `Set` and `Map` they're keys though. It's sorted in that you can reference `data[1]` and get that element, but I don't know the keys are necessarily sorted. This guy says "V8 team explains how some memory optimization was done on its hashtable implementation for Map, Set, WeakSet, and WeakMap: Optimizing hash tables: hiding the hash code Based on 1 and 2: V8's Set and Map's get & set & add & has time complexity practically is O(1)." https://stackoverflow.com/questions/33611509/es6-map-and-set-complexity-v8-implementation https://stackoverflow.com/questions/33611509/es6-map-and-set...

mpeg 3y ago

I wouldn't bother arguing with this guy, he deliberately misquoted me on every point to make it seem like what he's saying is correct Indeed I was talking about the internals of v8, and even linked a blog post explaining it, v8 is written in c++ so it doesn't use javascript data structures anyway.

_akhe 3y ago
Haha dude you think Python is fast, and said multi-process has nothing to do with JavaScript, so of course I'm going to write off anything you think at this point because you know nothing about dynamic languages. I missed the V8 bit because I was replying to a lot of people - your overall point is still terrible because JavaScript is a lot faster than Python. Think about the larger point you're making. Btw sometimes you say "it's just an OS feature" when convenient but you don't say "it's just an interpreter feature" (regarding V8) - I wonder at what point in the debate that will come out. That's why I hate these kinds of debates, they're all signaling and changing subjects and losing sight of the point being made. Whenever I'm talking about time complexity, I'm in a terrible conversation that I can't wait to get out of. The bottom line is everybody in the world except you knows Python is slow as hell, and for more than 1 reason.