Ask HN: What are you learning? • Hacker News Board

Re: Ask HN: What are you learning?

#751

Post by mildmelon » Mon, Apr 06, 2020, 1:58 PM UTC

I've been learning Korean, I recently found out that it is a language that was invented rather than evolving over time. It was created with the intention to be easy to learn. The entire alphabet is 24 characters, whereas Japanese has over 500 and Mandarin has a few thousand.

Each of the 24 characters follow very logical rules and build onto each other to build "blocks" of syllables. Each block must start with a consonant in the top-left, always followed by a vowel, and sometimes ends with a consonant. So the block always reads left-right, top-bottom and must always contain at least one consonant and vowel.

In addition, each syllable block has a phonetic sound. This means that it's really easy to read and pronounce, since there are no silent letters, with the one exception of single vowel syllable blocks. Which must start with a silent ㅇ(ng), for example the character ㅣ(i). So following the rule of a syllable block needing to start with a consonant you can't have a single ㅣ since it's a vowel, so you need to use ㅇ as a placeholder, thus creating ㅇㅣ(i).

Now if you want to create a word, like "child". You can put together the character ㅏ(a) and ㅣ(i). Since you can't have two vowels in the same block, we must use two blocks to create the word. This gives us ㅇㅏㅇㅣ (a-i).

The vowels consist entirely of horizontal and vertical lines, with a dash or double dash off to the left, right, top, or bottom. It's a very simple alphabet and an extremely interesting language. If anyone want's to learn more, feel free to checkout the Wiki page on Hangul for the full set of vowels, consonants, and double consonants. It's often said you can learn the Hangul alphabet in 90 minutes. If you want a solid intro course to Hangul, checkout this video https://www.youtube.com/watch?v=s5aobqyEaMQ

Re: Ask HN: What are you learning?

#752

Post by scythe » Mon, Apr 06, 2020, 2:00 PM UTC

mjfl wrote: post #333

Twisol wrote: post #275

I'm working through Aluffi's Algebra: Chapter Zero , which covers abstract algebra (groups, fields, vector spaces, etc.) with category theoretic foundations. I took undergraduate algebra several years ago, and I'm really interested in category theory from a compositionality perspective, so this is a good opportunity to brush up on both topics. Aluffi is really well-written. It assumes some degree of mathematical matu…

You know something? I know a little abstract algebra: groups, subgroups, quotient groups, and the relvent theorems behind them. It's been disappointingly useless to me though. Maybe someday I will take the quotient group of two matrix groups... I'm not sure though.

Most people start abstract algebra with groups, which is not surprising since the underlying definition is very simple and the basic examples are easy to understand. But abstract algebra only really starts to come into its own when you start to learn about rings and modules, which ultimately turn out to be important in proving most of the significant theorems in group theory as well.

One example I've been toying with recently is the link between complex and split-complex numbers, and the latter are isomorphic to a direct product of two copies of R. Putting these analogies together leads to a slight improvement of Karatsuba's complex number multiplication algorithm:

https://gist.github.com/scythe/9976568d9d49b3322a33c5cd55895...

The extra storage use does call into question whether this representation can be helpful in practice, but the fact that these abstractions can be unrolled into code is pretty cool.

Re: Ask HN: What are you learning?

#753

Post by kiliantics » Mon, Apr 06, 2020, 2:05 PM UTC

I've been rebuilding the engine of a 1980 Honda motorcycle for the last while. Just following the manual and reading on forums and watching youtube videos. Yesterday, I finally got it fully back together and put it on the bike and reassembled everything else. It didn't start perfectly but it did start, which was really satisfying. There is a little more "debugging" left to do on it but I believe I will get it back in shape eventually. All this from no knowledge of engine mechanics a few months ago, I now feel like I can competently talk about the different parts of a combustion engine and do some basic diagnosis for vehicle problems.

Doing this has been one of the best experiences in my life and it was a very cheap bike to buy and I only needed a pretty basic set of tools on top of it. I don't own other vehicles but I bet that, down the line, it will save me a lot of money that I may otherwise have given to mechanics. I would recommend doing this to anyone that has an interest in it, it doesn't take expert knowledge, just a healthy level of gumption :)

Re: Ask HN: What are you learning?

#754

Post by zebrafish » Mon, Apr 06, 2020, 2:15 PM UTC

Learning 3D modeling in blender through videos from Grant Abbitt on YouTube. No idea what I'm going to do with that skill, it's just something I've always wanted to learn since Halo: Custom Edition came out on PC.

Re: Ask HN: What are you learning?

#755

Post by tartoran » Mon, Apr 06, 2020, 2:23 PM UTC

Im learning Scheme/Racket. I started from HTDP and moving on from there, so far I am loving it, havent been this excited in a while. I am also ramping up on F# and the community is growing and quite nice. I recommend Scott Wlaschin’s Domain Modleling in F# and his website fsharpforfunandprofit.

I am learning Latin and Spanish on Duolingo but thats more at the hobby level, about 10 min a day.

Re: Ask HN: What are you learning?

#756

Post by war1025 » Mon, Apr 06, 2020, 2:30 PM UTC

Breza wrote: post #509

war1025 wrote: post #400

I spent a couple hours this afternoon trying to start a fire with a cheap magnifying glass. If I had a decent tinder bundle I would have succeeded. Amazing how easy it is to get something smoking. Burnt a whole bunch of stuff, just never managed to get to fire.

May I suggest dryer lint as tinder. I keep all of mine in a bucket for just that purpose.

I'll have to give that a try next time.

We have some Lamb's Ear [1] in our garden that I had a decent amount of success with, but I used up most of the dead stuff from last year over the course of the afternoon.

[1] https://en.wikipedia.org/wiki/Stachys_byzantina

Re: Ask HN: What are you learning?

#757

Post by jjice » Mon, Apr 06, 2020, 2:30 PM UTC

I've been reading through Lion's Commentary of Unix V6. Very interesting to finally understand how multiple processes and scheduling is done, as that was always a mystery to me. There's a great version where the source and the commentary are side by side: https://warsus.github.io/lions-/

Re: Ask HN: What are you learning?

#758

Post by qxfys » Mon, Apr 06, 2020, 2:38 PM UTC

I am learning how wireguard [1] works, and try to prove their claim that it is suitable for small embedded device, i.e. this one [2].

[1] https://www.wireguard.com/

[2] https://github.com/Zolertia/Resources/wiki/Firefly

Re: Ask HN: What are you learning?

#759

Post by azepoi » Mon, Apr 06, 2020, 2:39 PM UTC

mildmelon wrote: post #751

I've been learning Korean, I recently found out that it is a language that was invented rather than evolving over time. It was created with the intention to be easy to learn. The entire alphabet is 24 characters, whereas Japanese has over 500 and Mandarin has a few thousand. Each of the 24 characters follow very logical rules and build onto each other to build "blocks" of syllables. Each block must start with a conso…

The alphabet was created not the language itself. Hangul is indeed designed for the Korean language, a natural language.

Re: Ask HN: What are you learning?

#760

Post by cheese4242 » Mon, Apr 06, 2020, 2:40 PM UTC

DeathArrow wrote: post #655

shitoujizu wrote: post #396

Earlier quoted context omitted.

sometimes feels very sad about this since one's value should be reflected by the awesome projects he has done. I think it's just laziness of the FAANG companies. If the interviewer is well prepared and keeps digging the resume, then he should know the candidate is good or not. But by leetcoding, it's simpler for them, just keep asking the repeated questions.

I think that if your hobby projects will be important for many people: i.e. you develop something with the importance npm, or Ruby on Rails, or Vue.js, FAANG companies will make you offers without asking you leetcode kind of questions.

I read that the guy who invented Homebrew still had to go through the leetcode interview at Google (which they failed) so I'm not sure if they ever waive the interview requirements?